[issue45077] multiprocessing.Pool(64) crashes on Windows

[Kagami Sascha Rosylight]

Kagami Sascha Rosylight <saschanaz at outlook.com> added the comment:

The argument-less instantiation also fails, which is worse.

```
>>> multiprocessing.Pool()
<multiprocessing.pool.Pool state=RUN pool_size=64>
>>> Exception in thread Thread-1:
Traceback (most recent call last):
  File "C:\Users\sasch\AppData\Local\Programs\Python\Python39\lib\threading.py", line 973, in _bootstrap_inner
    self.run()
  File "C:\Users\sasch\AppData\Local\Programs\Python\Python39\lib\threading.py", line 910, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Users\sasch\AppData\Local\Programs\Python\Python39\lib\multiprocessing\pool.py", line 519, in _handle_workers
    cls._wait_for_updates(current_sentinels, change_notifier)
  File "C:\Users\sasch\AppData\Local\Programs\Python\Python39\lib\multiprocessing\pool.py", line 499, in _wait_for_updates
    wait(sentinels, timeout=timeout)
  File "C:\Users\sasch\AppData\Local\Programs\Python\Python39\lib\multiprocessing\connection.py", line 884, in wait
    ready_handles = _exhaustive_wait(waithandle_to_obj.keys(), timeout)
  File "C:\Users\sasch\AppData\Local\Programs\Python\Python39\lib\multiprocessing\connection.py", line 816, in _exhaustive_wait
    res = _winapi.WaitForMultipleObjects(L, False, timeout)
ValueError: need at most 63 handles, got a sequence of length 66
```

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue45077>
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