bpo-36763: Rename private Python initialization functions (GH-13511)

* Rename private C functions:

  * _Py_Initialize_ReconfigureCore => pyinit_core_reconfigure
  * _Py_InitializeCore_impl => pyinit_core_config
  * _Py_InitializeCore = > pyinit_core
  * _Py_InitializeMainInterpreter => pyinit_main
  * init_python => pyinit_python

* Rename _testembed.c commands: add "test_" prefix.
diff --git a/Lib/test/test_embed.py b/Lib/test/test_embed.py
index 8101e70..bd0451a 100644
--- a/Lib/test/test_embed.py
+++ b/Lib/test/test_embed.py
@@ -82,7 +82,7 @@
         return out, err
 
     def run_repeated_init_and_subinterpreters(self):
-        out, err = self.run_embedded_interpreter("repeated_init_and_subinterpreters")
+        out, err = self.run_embedded_interpreter("test_repeated_init_and_subinterpreters")
         self.assertEqual(err, "")
 
         # The output from _testembed looks like this:
@@ -172,7 +172,7 @@
     def test_forced_io_encoding(self):
         # Checks forced configuration of embedded interpreter IO streams
         env = dict(os.environ, PYTHONIOENCODING="utf-8:surrogateescape")
-        out, err = self.run_embedded_interpreter("forced_io_encoding", env=env)
+        out, err = self.run_embedded_interpreter("test_forced_io_encoding", env=env)
         if support.verbose > 1:
             print()
             print(out)
@@ -218,7 +218,7 @@
         is initialized (via Py_Initialize()).
         """
         env = dict(os.environ, PYTHONPATH=os.pathsep.join(sys.path))
-        out, err = self.run_embedded_interpreter("pre_initialization_api", env=env)
+        out, err = self.run_embedded_interpreter("test_pre_initialization_api", env=env)
         if MS_WINDOWS:
             expected_path = self.test_exe
         else:
@@ -234,7 +234,7 @@
         """
         env = dict(os.environ, PYTHONPATH=os.pathsep.join(sys.path))
         out, err = self.run_embedded_interpreter(
-                        "pre_initialization_sys_options", env=env)
+                        "test_pre_initialization_sys_options", env=env)
         expected_output = (
             "sys.warnoptions: ['once', 'module', 'default']\n"
             "sys._xoptions: {'not_an_option': '1', 'also_not_an_option': '2'}\n"
@@ -249,7 +249,7 @@
         calling PyEval_InitThreads() must not crash. PyGILState_Ensure() must
         call PyEval_InitThreads() for us in this case.
         """
-        out, err = self.run_embedded_interpreter("bpo20891")
+        out, err = self.run_embedded_interpreter("test_bpo20891")
         self.assertEqual(out, '')
         self.assertEqual(err, '')
 
@@ -258,7 +258,7 @@
         bpo-33932: Calling Py_Initialize() twice should do nothing (and not
         crash!).
         """
-        out, err = self.run_embedded_interpreter("initialize_twice")
+        out, err = self.run_embedded_interpreter("test_initialize_twice")
         self.assertEqual(out, '')
         self.assertEqual(err, '')
 
@@ -266,12 +266,12 @@
         """
         bpo-34008: Calling Py_Main() after Py_Initialize() must not fail.
         """
-        out, err = self.run_embedded_interpreter("initialize_pymain")
+        out, err = self.run_embedded_interpreter("test_initialize_pymain")
         self.assertEqual(out.rstrip(), "Py_Main() after Py_Initialize: sys.argv=['-c', 'arg2']")
         self.assertEqual(err, '')
 
     def test_run_main(self):
-        out, err = self.run_embedded_interpreter("run_main")
+        out, err = self.run_embedded_interpreter("test_run_main")
         self.assertEqual(out.rstrip(), "_Py_RunMain(): sys.argv=['-c', 'arg2']")
         self.assertEqual(err, '')
 
@@ -632,13 +632,13 @@
         self.check_global_config(config)
 
     def test_init_default_config(self):
-        self.check_config("init_initialize_config", api=API_COMPAT)
+        self.check_config("test_init_initialize_config", api=API_COMPAT)
 
     def test_preinit_compat_config(self):
-        self.check_config("preinit_compat_config", api=API_COMPAT)
+        self.check_config("test_preinit_compat_config", api=API_COMPAT)
 
     def test_init_compat_config(self):
-        self.check_config("init_compat_config", api=API_COMPAT)
+        self.check_config("test_init_compat_config", api=API_COMPAT)
 
     def test_init_global_config(self):
         preconfig = {
@@ -660,7 +660,7 @@
             'user_site_directory': 0,
             'pathconfig_warnings': 0,
         }
-        self.check_config("init_global_config", config, preconfig,
+        self.check_config("test_init_global_config", config, preconfig,
                           api=API_COMPAT)
 
     def test_init_from_config(self):
@@ -705,7 +705,7 @@
             'check_hash_pycs_mode': 'always',
             'pathconfig_warnings': 0,
         }
-        self.check_config("init_from_config", config, preconfig,
+        self.check_config("test_init_from_config", config, preconfig,
                           api=API_COMPAT)
 
     def test_init_env(self):
@@ -732,7 +732,7 @@
             'faulthandler': 1,
             'warnoptions': ['EnvVar'],
         }
-        self.check_config("init_env", config, preconfig,
+        self.check_config("test_init_env", config, preconfig,
                           api=API_COMPAT)
 
     def test_init_env_dev_mode(self):
@@ -740,7 +740,7 @@
         config = dict(dev_mode=1,
                       faulthandler=1,
                       warnoptions=['default'])
-        self.check_config("init_env_dev_mode", config, preconfig,
+        self.check_config("test_init_env_dev_mode", config, preconfig,
                           api=API_COMPAT)
 
     def test_init_env_dev_mode_alloc(self):
@@ -748,7 +748,7 @@
         config = dict(dev_mode=1,
                       faulthandler=1,
                       warnoptions=['default'])
-        self.check_config("init_env_dev_mode_alloc", config, preconfig,
+        self.check_config("test_init_env_dev_mode_alloc", config, preconfig,
                           api=API_COMPAT)
 
     def test_init_dev_mode(self):
@@ -760,7 +760,7 @@
             'dev_mode': 1,
             'warnoptions': ['default'],
         }
-        self.check_config("init_dev_mode", config, preconfig,
+        self.check_config("test_init_dev_mode", config, preconfig,
                           api=API_PYTHON)
 
     def test_preinit_parse_argv(self):
@@ -777,7 +777,7 @@
             'warnoptions': ['default'],
             'xoptions': ['dev'],
         }
-        self.check_config("preinit_parse_argv", config, preconfig,
+        self.check_config("test_preinit_parse_argv", config, preconfig,
                           api=API_PYTHON)
 
     def test_preinit_dont_parse_argv(self):
@@ -790,7 +790,7 @@
                      "-X", "dev", "-X", "utf8", "script.py"],
             'isolated': 0,
         }
-        self.check_config("preinit_dont_parse_argv", config, preconfig,
+        self.check_config("test_preinit_dont_parse_argv", config, preconfig,
                           api=API_ISOLATED)
 
     def test_init_isolated_flag(self):
@@ -799,7 +799,7 @@
             'use_environment': 0,
             'user_site_directory': 0,
         }
-        self.check_config("init_isolated_flag", config, api=API_PYTHON)
+        self.check_config("test_init_isolated_flag", config, api=API_PYTHON)
 
     def test_preinit_isolated1(self):
         # _PyPreConfig.isolated=1, _PyCoreConfig.isolated not set
@@ -808,7 +808,7 @@
             'use_environment': 0,
             'user_site_directory': 0,
         }
-        self.check_config("preinit_isolated1", config, api=API_COMPAT)
+        self.check_config("test_preinit_isolated1", config, api=API_COMPAT)
 
     def test_preinit_isolated2(self):
         # _PyPreConfig.isolated=0, _PyCoreConfig.isolated=1
@@ -817,16 +817,19 @@
             'use_environment': 0,
             'user_site_directory': 0,
         }
-        self.check_config("preinit_isolated2", config, api=API_COMPAT)
+        self.check_config("test_preinit_isolated2", config, api=API_COMPAT)
 
     def test_preinit_isolated_config(self):
-        self.check_config("preinit_isolated_config", api=API_ISOLATED)
+        self.check_config("test_preinit_isolated_config", api=API_ISOLATED)
 
     def test_init_isolated_config(self):
-        self.check_config("init_isolated_config", api=API_ISOLATED)
+        self.check_config("test_init_isolated_config", api=API_ISOLATED)
+
+    def test_preinit_python_config(self):
+        self.check_config("test_preinit_python_config", api=API_PYTHON)
 
     def test_init_python_config(self):
-        self.check_config("init_python_config", api=API_PYTHON)
+        self.check_config("test_init_python_config", api=API_PYTHON)
 
     def test_init_dont_configure_locale(self):
         # _PyPreConfig.configure_locale=0
@@ -834,7 +837,7 @@
             'configure_locale': 0,
             'coerce_c_locale': 0,
         }
-        self.check_config("init_dont_configure_locale", {}, preconfig,
+        self.check_config("test_init_dont_configure_locale", {}, preconfig,
                           api=API_PYTHON)
 
     def test_init_read_set(self):
@@ -842,7 +845,7 @@
             'program_name': './init_read_set',
             'executable': 'my_executable',
         }
-        self.check_config("init_read_set", core_config,
+        self.check_config("test_init_read_set", core_config,
                           api=API_PYTHON,
                           add_path="init_read_set_path")
 
@@ -855,7 +858,7 @@
             'run_command': code + '\n',
             'parse_argv': 1,
         }
-        self.check_config("init_run_main", core_config, api=API_PYTHON)
+        self.check_config("test_init_run_main", core_config, api=API_PYTHON)
 
     def test_init_main(self):
         code = ('import _testinternalcapi, json; '
@@ -867,7 +870,7 @@
             'parse_argv': 1,
             '_init_main': 0,
         }
-        self.check_config("init_main", core_config,
+        self.check_config("test_init_main", core_config,
                           api=API_PYTHON,
                           stderr="Run Python code before _Py_InitializeMain")
 
@@ -879,7 +882,7 @@
             'run_command': 'pass\n',
             'use_environment': 0,
         }
-        self.check_config("init_parse_argv", core_config, api=API_PYTHON)
+        self.check_config("test_init_parse_argv", core_config, api=API_PYTHON)
 
     def test_init_dont_parse_argv(self):
         pre_config = {
@@ -890,7 +893,7 @@
             'argv': ['./argv0', '-E', '-c', 'pass', 'arg1', '-v', 'arg3'],
             'program_name': './argv0',
         }
-        self.check_config("init_dont_parse_argv", core_config, pre_config,
+        self.check_config("test_init_dont_parse_argv", core_config, pre_config,
                           api=API_PYTHON)