gh-117721: use PyMutex in _thread.lock

[kumaraditya303]

Changes:

• use PyMutex instead of PyThread_type_lock
• as enhancement use Py_TPFLAGS_MANAGED_WEAKREF

• Issue: _thread.lock.release() is not thread-safe in free-threaded builds #117721

[colesbury]

LGTM. Minor comments below

[colesbury]

@kumaraditya303, see #125058. We should check if this makes threading.Lock.acquire() interruptible on Windows. If so, it probably deserves a NEWS entry and possibly a documentation update.

[kumaraditya303]

We should check if this makes threading.Lock.acquire() interruptible on Windows. If so, it probably deserves a NEWS entry and possibly a documentation update.

It doesn't, it is not interruptible.

[miss-islington-app]

Thanks @kumaraditya303 for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @kumaraditya303, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker fca552993da32044165223eec2297b6aaaac60ad 3.13

[bedevere-app]

GH-125116 is a backport of this pull request to the 3.13 branch.

[vstinner]

This change introduced a regression: #125451.

[vstinner]

#125116 is a backport of this pull request to the 3.13 branch.

IMO this change should not be backported to 3.13 in a bugfix release. It's too big, it can cause regression as you can see.

[colesbury]

I don't think there's a bug in _thread.lock, but I'm okay with reverting the backport