inspect: Fix getfullargspec to support builtin module-level functions. Issue #20711
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 711d2a3..95c1b32 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -643,6 +643,13 @@
         self.assertFullArgSpecEquals(_pickle.Pickler(io.BytesIO()).dump,
                                      args_e=['self', 'obj'], formatted='(self, obj)')
 
+        self.assertFullArgSpecEquals(
+             os.stat,
+             args_e=['path'],
+             kwonlyargs_e=['dir_fd', 'follow_symlinks'],
+             kwonlydefaults_e={'dir_fd': None, 'follow_symlinks': True},
+             formatted='(path, *, dir_fd=None, follow_symlinks=True)')
+
     @cpython_only
     @unittest.skipIf(MISSING_C_DOCSTRINGS,
                      "Signature information for builtins requires docstrings")