gh-136003: Close file descriptors in test

[encukou]

This should fix FD leaks introduced in GH-136004

• Issue: Some pre-finalization callbacks can create other callbacks #136003

[ZeroIntensity]

Thanks, sorry about this!

[encukou]

!buildbot AMD64.Fedora.Stable.Refleaks

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @encukou for commit 4f73b8c 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F139225%2Fmerge

The command will test the builders whose names match following regular expression: AMD64.Fedora.Stable.Refleaks

The builders matched are:

• AMD64 Fedora Stable Refleaks PR

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Ubuntu Shared 3.x (tier-1) has failed when building commit 61e54e5.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/506/builds/11471) and take a look at the build logs.
4. Check if the failure is related to this commit (61e54e5) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/506/builds/11471

Failed tests:

• test_interpreters

Failed subtests:

• test_keyboard_interrupt_in_thread_running_interp - test.test_interpreters.test_api.InterpreterObjectTests.test_keyboard_interrupt_in_thread_running_interp

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/srv/buildbot/buildarea/3.x.bolen-ubuntu/build/Lib/test/test_interpreters/test_api.py", line 462, in test_keyboard_interrupt_in_thread_running_interp
    self.assertEqual(retcode, 0)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^
AssertionError: -2 != 0