bpo-37224: Improve test__xxsubinterpreters.DestroyTests (GH-18058)


Adds an additional assertion check based on a race condition for `test__xxsubinterpreters.DestroyTests.test_still_running` discovered in the bpo issue.

https://bugs.python.org/issue37224
(cherry picked from commit f03a8f8d5001963ad5b5b28dbd95497e9cc15596)

Co-authored-by: Kyle Stanley <aeros167@gmail.com>
1 file changed