https://buildbot.python.org/all/#/builders/58/builds/2098/steps/3/logs/stdio

Process Process-2:
Traceback (most recent call last):
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\multiprocessing\process.py", line 302, in _bootstrap
    self.run()
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\multiprocessing\process.py", line 99, in run
    self._target(*self._args, **self._kwargs)
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\_test_multiprocessing.py", line 4585, in child
    join_process(p)
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\_test_multiprocessing.py", line 88, in join_process
    support.join_thread(process, timeout=TIMEOUT)
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\support\__init__.py", line 2244, in join_thread
    raise AssertionError(msg)
AssertionError: failed to join the thread in 30.0 seconds
Timeout (0:15:00)!


======================================================================
FAIL: test_abort (test.test_multiprocessing_spawn.WithManagerTestBarrier)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\_test_multiprocessing.py", line 1765, in test_abort
    self.assertEqual(len(results2), self.N-1)
AssertionError: 5 != 4
----------------------------------------------------------------------
Ran 344 tests in 717.841s
FAILED (failures=1, skipped=40)
1 test failed again:
    test_multiprocessing_spawn
== Tests result: FAILURE then FAILURE ==
388 tests OK.

Looks like a race condition, new builds are OK.