gh-119121: Fix and test async.staggered.staggered_race

[sobolevn]

I've added a couple of tests for this function as well, to prevent simple future regressions.

Please, note that this set of tests is clearly not enough to cover all the cases in this function. Right now it only covers several simple use-cases. In the future we can also test:

• loop= argument
• Cleanups of running tasks
• __debug__ route
• delay corner cases
• etc

But, I think that testing green path is good enough for now.
I can commit more tests in the next PRs, since they will require quite a lot of effort.

Refs #114282
This PR does need a 3.13 backport.

• Issue: asyncio.staggered is missing typing import #119121

[JelleZijlstra]

Thanks!

[miss-islington-app]

Thanks @sobolevn for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-119206 is a backport of this pull request to the 3.13 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 FreeBSD14 3.13 has failed when building commit 3a8ab99.

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/all/#builders/1481/builds/48) and take a look at the build logs.
4. Check if the failure is related to this commit (3a8ab99) 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/all/#builders/1481/builds/48

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

==

Click to see traceback logs

Traceback (most recent call last): File "<frozen getpath>", line 355, in <module>ValueError: embedded null byte Warning -- Uncaught thread exception: InterpreterError Exception in thread Thread-188 (task): RuntimeError: error evaluating path Traceback (most recent call last): File "/home/buildbot/buildarea/3.13.opsec-fbsd14/build/Lib/threading.py", line 1039, in _bootstrap_innerself.run() ~~~~~~~~^^ File "/home/buildbot/buildarea/3.13.opsec-fbsd14/build/Lib/threading.py", line 990, in runself._target(*self._args, **self._kwargs) ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/buildbot/buildarea/3.13.opsec-fbsd14/build/Lib/test/test_interpreters/test_stress.py", line 29, in task interp = interpreters.create() File "/home/buildbot/buildarea/3.13.opsec-fbsd14/build/Lib/test/support/interpreters/__init__.py", line 76, in createid= _interpreters.create(reqrefs=True) interpreters.InterpreterError: interpreter creation failed k