[3.14] gh-136870: fix data race in `PyThreadState_Clear` on `sys_tracing_threads...

[3.14] gh-136870: fix data race in `PyThreadState_Clear` on `sys_tracing_threads` (GH-136951) (#136953)

gh-136870: fix data race in `PyThreadState_Clear` on `sys_tracing_threads` (GH-136951)

In free-threading, multiple threads can be cleared concurrently as such the modifications on `sys_tracing_threads` should be done while holding the profile lock, otherwise it can race with other threads setting up profiling.
(cherry picked from commit f183996eb77fd2d5662c62667298c292c943ebf5)

Co-authored-by: Kumar Aditya <kumaraditya@python.org>