Replace all occurrences of sys.is_finalizing

[fjetter]

We stumbled again over some noisiness during interpreter shutdown inside of the Futures __del__. For this we implemented the is_python_shutting_down utility which has slightly different semantics than the actual python sys.is_finalizing. I have to admit that I don't fully understand the differences but from what I can tell our toggle is set a little bit earlier. Reviewing all of our usage of sys.is_finalizing I think it is safe to use the utility everywhere for simplicity.

[github-actions]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

    27 files  ±  0      27 suites  ±0   10h 7m 0s ⏱️ + 26m 16s
 3 960 tests +  8   3 850 ✅ +  9    109 💤 ±0  1 ❌  - 1 
49 809 runs  +118  47 518 ✅ +126  2 290 💤  - 7  1 ❌  - 1 

For more details on these failures, see this check.

Results for commit a41ec76. ± Comparison against base commit d93d498.

♻️ This comment has been updated with latest results.

[hendrikmakait]

It looks like test_quiet_close_process isn't happy with these changes.

[fjetter]

if tests keep failing, let's just change the one in Future and keep it at that. No point in wasting our time hunting this down

[hendrikmakait]

if tests keep failing, let's just change the one in Future and keep it at that. No point in wasting our time hunting this down

Looks like I'm playing ping-pong with test failures. I'll reactivate my PR.

[hendrikmakait]

Looks like I'm playing ping-pong with test failures. I'll reactivate my PR.

I may have figured it out.