gh-127582: Make object resurrection thread-safe for free threading. (GH-127612)

gh-127582: Make object resurrection thread-safe for free threading. (GH-127612)

Objects may be temporarily "resurrected" in destructors when calling
finalizers or watcher callbacks. We previously undid the resurrection
by decrementing the reference count using `Py_SET_REFCNT`. This was not
thread-safe because other threads might be accessing the object
(modifying its reference count) if it was exposed by the finalizer,
watcher callback, or temporarily accessed by a racy dictionary or list
access.

This adds internal-only thread-safe functions for temporary object
resurrection during destructors.