Try to fix sporadic failure in test_thread/test_threading

diff --cc Lib/test/lock_tests.py
index 005c912fcf610ae0cd10eabba4e4edad43522837,22c690059297a8ceb3c5db90ff5cfc4be01de64f..ff30d41fb80bfb436c83885952de35239faa92fd
--- 1/Lib/test/lock_tests.py
--- 2/Lib/test/lock_tests.py
+++ b/Lib/test/lock_tests.py
@@@ -149,34 -141,14 +149,40 @@@ class BaseLockTests(BaseTestCase)
          # We run many threads in the hope that existing threads ids won't
          # be recycled.
          Bunch(f, 15).wait_for_finished()
-         self.assertEqual(n, len(threading.enumerate()))
+         if len(threading.enumerate()) != n:
+             # There is a small window during which a Thread instance's
+             # target function has finished running, but the Thread is still
+             # alive and registered.  Avoid spurious failures by waiting a
+             # bit more (seen on a buildbot).
+             time.sleep(0.4)
+             self.assertEqual(n, len(threading.enumerate()))
  
 +    def test_timeout(self):
 +        lock = self.locktype()
 +        # Can't set timeout if not blocking
 +        self.assertRaises(ValueError, lock.acquire, 0, 1)
 +        # Invalid timeout values
 +        self.assertRaises(ValueError, lock.acquire, timeout=-100)
 +        self.assertRaises(OverflowError, lock.acquire, timeout=1e100)
 +        self.assertRaises(OverflowError, lock.acquire, timeout=TIMEOUT_MAX + 1)
 +        # TIMEOUT_MAX is ok
 +        lock.acquire(timeout=TIMEOUT_MAX)
 +        lock.release()
 +        t1 = time.time()
 +        self.assertTrue(lock.acquire(timeout=5))
 +        t2 = time.time()
 +        # Just a sanity test that it didn't actually wait for the timeout.
 +        self.assertLess(t2 - t1, 5)
 +        results = []
 +        def f():
 +            t1 = time.time()
 +            results.append(lock.acquire(timeout=0.5))
 +            t2 = time.time()
 +            results.append(t2 - t1)
 +        Bunch(f, 1).wait_for_finished()
 +        self.assertFalse(results[0])
 +        self.assertTimeout(results[1], 0.5)
 +
  
  class LockTests(BaseLockTests):
      """