Issue #12096: Fix a race condition in test_threading.test_waitfor(). Patch
written by Charles-François Natali.
diff --git a/Lib/test/lock_tests.py b/Lib/test/lock_tests.py
index ff30d41..f0a2411 100644
--- a/Lib/test/lock_tests.py
+++ b/Lib/test/lock_tests.py
@@ -472,7 +472,7 @@
                 self.assertEqual(state, 4)
         b = Bunch(f, 1)
         b.wait_for_started()
-        for i in range(5):
+        for i in range(4):
             time.sleep(0.01)
             with cond:
                 state += 1