Issue #21925: Fix test_warnings for release mode

Use -Wd comment line option to log the ResourceWarning.

Lib/test/test_warnings/__init__.py

@@ -962,12 +962,12 @@ a=A()
         # don't import the warnings module
         # (_warnings will try to import it)
         code = "f = open(%a)" % __file__
-        rc, out, err = assert_python_ok("-c", code)
+        rc, out, err = assert_python_ok("-Wd", "-c", code)
         self.assertTrue(err.startswith(expected), ascii(err))
 
         # import the warnings module
         code = "import warnings; f = open(%a)" % __file__
-        rc, out, err = assert_python_ok("-c", code)
+        rc, out, err = assert_python_ok("-Wd", "-c", code)
         self.assertTrue(err.startswith(expected), ascii(err))