I created https://github.com/python/cpython/pull/20485 to skip the unstable tests until someone fix them. IMO it's better to skip the test than reverting the fix, since the fix does fix a race condition.

The test is still failing on buildbots which makes analysis of buildbot failures more difficult. For example, a SQLite change got 3 different 4 different bugs on buildbots:
https://github.com/python/cpython/pull/20448#issuecomment-635350054

See the "revert on fail" policy for buildbots:
https://pythondev.readthedocs.io/ci.html#revert-on-fail


> I'm also a bit skeptical about relying on `time.sleep(0.01)` at the end of the loop in `_basetest_sock_recv_racing()`

Yeah, please avoid sleep as a synchronization primitive:
https://pythondev.readthedocs.io/unstable_tests.html#don-t-use-sleep-as-synchronization