Another TLS 1.3 client cert auth test is flaky, too.
https://buildbot.python.org/all/#/builders/577/builds/14/steps/4/logs/stdio
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FAIL: test_pha_required_nocert (test.test_ssl.TestPostHandshakeAuth)
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Traceback (most recent call last):
File "D:\buildarea\pull_request.bolen-windows10\build\lib\test\test_ssl.py", line 4412, in test_pha_required_nocert
s.recv(1024)
AssertionError: SSLError not raised