We shouldn't be entering invalid executors, it rather invalidates the invalidation.

[markshannon]

Bug report

Bug description:

ENTER_EXECUTOR doesn't check if an executor is invalid. We currently get away with this because only instrumentation invalidates executors, and it cleans up the ENTER_EXECUTORs.
It would be safer if ENTER_EXECUTOR check for invalid executors, and it would reduce the coupling between executors and instrumentation.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• GH-113595: Don't enter invalid executor #113596