Issue #25220, libregrtest: Set support.use_resources in setup_tests()

* Rename setup_python() to setup_tests()
* Remove use_resources parameter of runtest()
diff --git a/Lib/test/libregrtest/main.py b/Lib/test/libregrtest/main.py
index e685970..9ca407a 100644
--- a/Lib/test/libregrtest/main.py
+++ b/Lib/test/libregrtest/main.py
@@ -10,7 +10,7 @@
     findtests, runtest_ns,
     STDTESTS, NOTTESTS, PASSED, FAILED, ENV_CHANGED, SKIPPED, RESOURCE_DENIED)
 from test.libregrtest.cmdline import _parse_args
-from test.libregrtest.setup import setup_python
+from test.libregrtest.setup import setup_tests
 from test import support
 try:
     import gc
@@ -312,7 +312,6 @@
 
     def run_tests(self):
         support.verbose = self.ns.verbose   # Tell tests to be moderately quiet
-        support.use_resources = self.ns.use_resources
 
         if self.ns.forever:
             def test_forever(tests):
@@ -361,7 +360,7 @@
         if self.ns.wait:
             input("Press any key to continue...")
 
-        setup_python(self.ns)
+        setup_tests(self.ns)
 
         self.find_tests(tests)
         self.run_tests()