bpo-33671: Add support.MS_WINDOWS and support.MACOS (GH-7800)

* Add support.MS_WINDOWS: True if Python is running on Microsoft Windows.
* Add support.MACOS: True if Python is running on Apple macOS.
* Replace support.is_android with support.ANDROID
* Replace support.is_jython with support.JYTHON
* Cleanup code to initialize unix_shell
diff --git a/Lib/test/test_codeop.py b/Lib/test/test_codeop.py
index 98da26f..8d14ad3 100644
--- a/Lib/test/test_codeop.py
+++ b/Lib/test/test_codeop.py
@@ -3,12 +3,12 @@
    Nick Mathewson
 """
 import unittest
-from test.support import is_jython
+from test import support
 
 from codeop import compile_command, PyCF_DONT_IMPLY_DEDENT
 import io
 
-if is_jython:
+if support.JYTHON:
     import sys
 
     def unify_callables(d):
@@ -21,7 +21,7 @@
 
     def assertValid(self, str, symbol='single'):
         '''succeed iff str is a valid piece of code'''
-        if is_jython:
+        if support.JYTHON:
             code = compile_command(str, "<input>", symbol)
             self.assertTrue(code)
             if symbol == "single":
@@ -60,7 +60,7 @@
         av = self.assertValid
 
         # special case
-        if not is_jython:
+        if not support.JYTHON:
             self.assertEqual(compile_command(""),
                              compile("pass", "<input>", 'single',
                                      PyCF_DONT_IMPLY_DEDENT))