[3.13] gh-125966: fix use-after-free on `fut->fut_callback0` due to an evil callback's `__eq__` in asyncio (GH-125967) (#126047)

gh-125966: fix use-after-free on `fut->fut_callback0` due to an evil callback's `__eq__` in asyncio (GH-125967)
(cherry picked from commit ed5059eeb1aa50b481957307db5a34b937497382)

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>