[3.12] gh-128615: Cover pickling of ParamSpecArgs and ParamSpecKwargs (GH-128616) (#128626)

Co-authored-by: sobolevn <mail@sobolevn.me>

Lib/test/test_typing.py

@@ -4838,6 +4838,18 @@ class GenericTests(BaseTestCase):
                 x = pickle.loads(z)
                 self.assertEqual(s, x)
 
+        # Test ParamSpec args and kwargs
+        global PP
+        PP = ParamSpec('PP')
+        for thing in [PP.args, PP.kwargs]:
+            for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+                with self.subTest(thing=thing, proto=proto):
+                    self.assertEqual(
+                        pickle.loads(pickle.dumps(thing, proto)),
+                        thing,
+                    )
+        del PP
+
     def test_copy_and_deepcopy(self):
         T = TypeVar('T')
         class Node(Generic[T]): ...