test_multiprocessing_spawn.test_processes: test_waitfor_timeout() failed on GHA Windows x64

[vstinner]

GHA Windows x64:

FAIL: test_waitfor_timeout (test.test_multiprocessing_spawn.test_processes.WithProcessesTestCondition.test_waitfor_timeout)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\cpython\cpython\Lib\test\_test_multiprocessing.py", line 1683, in test_waitfor_timeout
    self.assertTrue(success.value)
AssertionError: 0 is not true

build: https://github.com/python/cpython/actions/runs/6299237551/job/17100847177?pr=109828

Linked PRs

• gh-109840: Fix multiprocessing test_waitfor_timeout() #110428
• [3.12] gh-109840: Fix multiprocessing test_waitfor_timeout() (GH-110428) #110430
• [3.11] gh-109840: Fix multiprocessing test_waitfor_timeout() (GH-110428) #110431