Investigate preventing resurrection of python objects

[jhugman]

Should this similarly poison the object on the python side, like we do in Kotlin? IIRC it is possible that someone might subclass one of these and extend __del__ in a way that resurrects the the python-side object after the rust-side destructor has been called. (They really shouldn't do that, but it's possible).

Originally posted by @rfk in #196

┆Issue is synchronized with this Jira Task
┆Issue Number: UNIFFI-10