[3.11] GH-100892: Fix race in clearing threading.local (GH-100922). (#100937)

(cherry picked from commit 762745a124)

Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>

Lib/test/test_threading_local.py

@@ -3,6 +3,7 @@ import unittest
 from doctest import DocTestSuite
 from test import support
 from test.support import threading_helper
+from test.support.import_helper import import_module
 import weakref
 import gc
 
@@ -197,6 +198,18 @@ class BaseLocalTest:
         self.assertIsNone(wr())
 
 
+    def test_threading_local_clear_race(self):
+        # See https://github.com/python/cpython/issues/100892
+
+        _testcapi = import_module('_testcapi')
+        _testcapi.call_in_temporary_c_thread(lambda: None, False)
+
+        for _ in range(1000):
+            _ = threading.local()
+
+        _testcapi.join_temporary_c_thread()
+
+
 class ThreadLocalTest(unittest.TestCase, BaseLocalTest):
     _local = _thread._local