[3.13] gh-129185: Fix PyTraceMalloc_Untrack() at Python exit (#129191) (#129217)
gh-129185: Fix PyTraceMalloc_Untrack() at Python exit (#129191)
Support calling PyTraceMalloc_Track() and PyTraceMalloc_Untrack()
during late Python finalization.
* Call _PyTraceMalloc_Fini() later in Python finalization.
* Test also PyTraceMalloc_Untrack() without the GIL
* PyTraceMalloc_Untrack() now gets the GIL.
* Test also PyTraceMalloc_Untrack() in test_tracemalloc_track_race().
(cherry picked from commit 46c7e13c05)
(cherry picked from commit e3b3e01d6a)
* Eliminate all remaining uses of Py_SIZE and Py_SET_SIZE on PyLongObject, adding asserts.
* Change layout of size/sign bits in longobject to support future addition of immortal ints and tagged medium ints.
* Add functions to hide some internals of long object, and for setting sign and digit count.
* Replace uses of IS_MEDIUM_VALUE macro with _PyLong_IsCompact().
