gh-107803: fix thread safety issue in double linked list implementation

[kumaraditya303]

• Issue: Double linked list implementation for asyncio tasks #107803

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Ubuntu NoGIL Refleaks 3.x has failed when building commit 8223544.

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/1226/builds/2113) and take a look at the build logs.
4. Check if the failure is related to this commit (8223544) 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/1226/builds/2113

Failed tests:

• test_functools

Test leaking resources:

• test_functools: memory blocks

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

==

Click to see traceback logs

remote: Enumerating objects: 13, done. remote: Counting objects: 7% (1/13) remote: Counting objects: 15% (2/13) remote: Counting objects: 23% (3/13) remote: Counting objects: 30% (4/13) remote: Counting objects: 38% (5/13) remote: Counting objects: 46% (6/13) remote: Counting objects: 53% (7/13) remote: Counting objects: 61% (8/13) remote: Counting objects: 69% (9/13) remote: Counting objects: 76% (10/13) remote: Counting objects: 84% (11/13) remote: Counting objects: 92% (12/13) remote: Counting objects: 100% (13/13) remote: Counting objects: 100% (13/13), done. remote: Compressing objects: 16% (1/6) remote: Compressing objects: 33% (2/6) remote: Compressing objects: 50% (3/6) remote: Compressing objects: 66% (4/6) remote: Compressing objects: 83% (5/6) remote: Compressing objects: 100% (6/6) remote: Compressing objects: 100% (6/6), done. remote: Total 7 (delta 6), reused 1 (delta 1), pack-reused 0 
From https://github.com/python/cpython
* branch main -> FETCH_HEAD
Note: switching to '82235449b85165add62c1b200299456a50a1d097'.
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Turn off this advice by setting config variable advice.detachedHead to false
HEAD is now at 82235449b8 gh-107803: fix thread safety issue in double linked list implementation (#121007)
Switched to and reset branch 'main'
configure: WARNING: no system libmpdecimal found; falling back to bundled libmpdecimal (deprecated and scheduled for removal in Python 3.15)make: *** [Makefile:2252: buildbottest] Error 2