gh-142651: use NonCallableMock._lock for thread safety of call_count

[kumaraditya303]

• Issue: ThreadingMock.call_count is not thread safe #142651

Skipping news as the there is already a news entry in the original PR.

[kumaraditya303]

No failure in 300+ iterations:

0:07:48 load avg: 3.39 [356] test_unittest.testmock.testthreadingmock passed (51.5 sec) -- running (3): test_unittest.testmock.testthreadingmock (51.8 sec), test_unittest.testmock.testthreadingmock (51.7 sec), test_unittest.testmock.testthreadingmock (51.9 sec)
0:07:48 load avg: 3.39 [357] test_unittest.testmock.testthreadingmock passed (51.7 sec) -- running (3): test_unittest.testmock.testthreadingmock (51.8 sec), test_unittest.testmock.testthreadingmock (51.7 sec), test_unittest.testmock.testthreadingmock (51.9 sec)
0:07:48 load avg: 3.39 [358] test_unittest.testmock.testthreadingmock passed (51.8 sec) -- running (1): test_unittest.testmock.testthreadingmock (51.9 sec)
0:07:48 load avg: 3.39 [359] test_unittest.testmock.testthreadingmock passed (51.7 sec)
0:07:48 load avg: 3.39 [360] test_unittest.testmock.testthreadingmock passed (51.9 sec)

[chaope]

Hi @kumaraditya303 ,

I have two questions:

• why is NonCallableMock._lock reused here instead of a dedicated threading.Lock object for this part?
• Could we change call_count to a property that calculates len(call_args_list) when call_count is called? In this way, we can avoid a lock to improve performance.