Same bug on AMD64 FreeBSD Non-Debug 3.x:
https://buildbot.python.org/all/#/builders/214/builds/472

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ERROR: test_crash (test.test_concurrent_futures.ProcessPoolSpawnExecutorDeadlockTest) [crash during func execution on worker]
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Traceback (most recent call last):
  File "/usr/home/buildbot/python/3.x.koobs-freebsd-9e36.nondebug/build/Lib/test/test_concurrent_futures.py", line 1119, in test_crash
    executor.shutdown(wait=True)
  File "/usr/home/buildbot/python/3.x.koobs-freebsd-9e36.nondebug/build/Lib/concurrent/futures/process.py", line 721, in shutdown
    self._executor_manager_thread_wakeup.wakeup()
  File "/usr/home/buildbot/python/3.x.koobs-freebsd-9e36.nondebug/build/Lib/concurrent/futures/process.py", line 93, in wakeup
    self._writer.send_bytes(b"")
  File "/usr/home/buildbot/python/3.x.koobs-freebsd-9e36.nondebug/build/Lib/multiprocessing/connection.py", line 205, in send_bytes
    self._send_bytes(m[offset:offset + size])
  File "/usr/home/buildbot/python/3.x.koobs-freebsd-9e36.nondebug/build/Lib/multiprocessing/connection.py", line 416, in _send_bytes
    self._send(header + buf)
  File "/usr/home/buildbot/python/3.x.koobs-freebsd-9e36.nondebug/build/Lib/multiprocessing/connection.py", line 373, in _send
    n = write(self._handle, buf)
OSError: [Errno 9] Bad file descriptor

Stdout:
8.35s 

Stderr:
Warning -- threading_cleanup() failed to cleanup 0 threads (count: 0, dangling: 3)
Dangling thread: <_MainThread(MainThread, started 34369908736)>
Dangling thread: <_ExecutorManagerThread(Thread-114, stopped daemon 34396434432)>
Dangling thread: <Thread(QueueFeederThread, stopped daemon 34377508352)>

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