Another issue with the tests is that it has become terribly slow. It's taking about 45 minutes to complete 1 run of the test suite. A few days ago, it took only 10 - 15 minutes. And moreover I think test_threading is also modifying sys.gettrace. The logs have the full error message.

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0:33:17 load avg: 0.80 [307/426/2] test_signal
(Pdb) continue
Warning -- sys.gettrace was modified by test_signal
  Before: None
  After:  <bound method Bdb.trace_dispatch of <pdb.Pdb object at 0x0000021A5D2DCD70>>
test test_signal failed -- Traceback (most recent call last):
  File "C:\github\cpython\lib\test\test_signal.py", line 1345, in test_sigint
    signal.raise_signal(signal.SIGINT)
AssertionError: KeyboardInterrupt not raised

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0:38:22 load avg: 0.04 [353/426/3] test_threading
(Pdb) continue
(Pdb) continue
(Pdb) continue
(Pdb) continue
Warning -- sys.gettrace was modified by test_threading
  Before: None
  After:  <bound method Bdb.trace_dispatch of <pdb.Pdb object at 0x0000021A5D2DCD70>>

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