gh-92265: set meta_path and path_hooks correctly in test_reload_namespace_changed (GH-92275)

Previously, we were blocking the frozen imports and forcing the source
version to be used, but we did not fix up sys.meta_path or
sys.path_hooks, causing the frozen importers to leak into the source
version of the test.

Author: FFY00

Lib/test/test_importlib/test_api.py

@@ -301,7 +301,8 @@ def test_reload_namespace_changed(self):
         name = 'spam'
         with os_helper.temp_cwd(None) as cwd:
             with test_util.uncache('spam'):
-                with import_helper.DirsOnSysPath(cwd):
+                with test_util.import_state(path=[cwd]):
+                    self.init._bootstrap_external._install(self.init._bootstrap)
                     # Start as a namespace package.
                     self.init.invalidate_caches()
                     bad_path = os.path.join(cwd, name, '__init.py')