The race condition still exists in tests. Recent failure on AMD64 Windows8.1 Refleaks 3.x:
https://buildbot.python.org/all/#/builders/511/builds/249

0:03:31 load avg: 2.93 [ 42/432/1] test_threading failed (1 error) (1 min 12 sec) -- running: test_runpy (1 min 8 sec), test_pydoc (55.4 sec), test_io (1 min 29 sec)
beginning 6 repetitions
123456
...Warning -- Unraisable exceptionWarning -- Unraisable exceptionWarning -- Unraisable exception
Exception ignored in thread started by: 
<function Bunch.__init__.<locals>.task at 0x000000CA51433CD0>
Exception ignored in thread started by
Exception ignored in thread started by: Traceback (most recent call last):
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 49, in task
<function Bunch.__init__.<locals>.task at 0x000000CA51433CD0>: 
<function Bunch.__init__.<locals>.task at 0x000000CA51433CD0>
Traceback (most recent call last):
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 49, in task
Traceback (most recent call last):
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 49, in task
        f()f()    

f()  
       ^  ^^^^^

   File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 1021, in f
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 1021, in f
^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 1021, in f
        i = barrier.wait()i = barrier.wait()

         i = barrier.wait()  
             ^ ^^^ ^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 683, in wait

  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 683, in wait
^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 683, in wait
    self._wait(timeout)
    ^^^^    ^self._wait(timeout)^
^    self._wait(timeout)
 ^^ ^   ^  ^^ ^^^^^^^^^^^^^^^^^^^^^^^^^
^^  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 723, in _wait
^^^^^^^^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 723, in _wait
^^^^^    ^raise BrokenBarrierError^

     raise BrokenBarrierError  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 723, in _wait
   ^
^ ^ ^ ^ ^^^    ^^raise BrokenBarrierError^^
^^ ^^ ^^ ^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^threading.^^BrokenBarrierError^^: ^^^
^^^^^
^threading.BrokenBarrierError^: ^
^^^
threading.BrokenBarrierError: 
Warning -- Unraisable exception
Exception ignored in thread started by: <function Bunch.__init__.<locals>.task at 0x000000CA51433CD0>
Traceback (most recent call last):
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 49, in task
    f()
    ^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 1021, in f
    i = barrier.wait()
        ^^^^^^^^^^^^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 674, in wait
    self._enter() # Block while the barrier drains.
    ^^^^^^^^^^^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 698, in _enter
    raise BrokenBarrierError
    ^^^^^^^^^^^^^^^^^^^^^^^^
threading.BrokenBarrierError: 
test test_threading failed -- Traceback (most recent call last):
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 1026, in test_default_timeout
    self.run_threads(f)
    ^^^^^^^^^^^^^^^^^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 855, in run_threads
    f()
    ^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\test\lock_tests.py", line 1021, in f
    i = barrier.wait()
        ^^^^^^^^^^^^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 683, in wait
    self._wait(timeout)
    ^^^^^^^^^^^^^^^^^^^
  File "D:\buildarea\3.x.ware-win81-release.refleak\build\Lib\threading.py", line 721, in _wait
    raise BrokenBarrierError
    ^^^^^^^^^^^^^^^^^^^^^^^^
threading.BrokenBarrierError