Make sure that tp_free frees the int the same way as tp_dealloc would.
This fixes the problem that Barry reported on python-dev:
   >>> 23000 .__class__ = bool
crashes in the deallocator.  This was because int inherited tp_free
from object, which uses the default allocator.

2.2. Bugfix candidate.

(trivial change in backport: "freefunc" -> "destructor")

Original patch(es):
python/dist/src/Objects/intobject.c:2.82