Issue #14500: Fix importlib.test.import_.test_packages to clean up

after itself properly.

Lib/importlib/test/import_/test_packages.py

@@ -3,6 +3,7 @@ from . import util as import_util
 import sys
 import unittest
 import importlib
+from test import support
 
 
 class ParentModuleTests(unittest.TestCase):
@@ -38,7 +39,10 @@ class ParentModuleTests(unittest.TestCase):
                                          module_code={'mod': module_injection})
         with mock_modules as mock:
             with util.import_state(meta_path=[mock]):
-                submodule = import_util.import_(subname)
+                try:
+                    submodule = import_util.import_(subname)
+                finally:
+                    support.unload(subname)
 
 
 def test_main():