Ignore stdlib threading module in code collection

[jrbourbeau]

Closes #8526. I confirmed using this branch that things look as expected.

cc @crusaderky

• Tests added / passed
• Passes pre-commit run --all-files

[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 8m 23s ⏱️ + 4m 21s
 3 996 tests ±0   3 884 ✅ ±0    110 💤 ±0  2 ❌ ±0 
50 254 runs  ±0  47 957 ✅ +1  2 295 💤 ±0  2 ❌  - 1 

For more details on these failures, see this check.

Results for commit 82e055e. ± Comparison against base commit 390a5b5.

[hendrikmakait]

Thanks, @jrbourbeau!