bpo-41295: Reimplement the Carlo Verre "hackcheck" (GH-21528)


Walk down the MRO backwards to find the type that originally defined the final `tp_setattro`, then make sure we are not jumping over intermediate C-level bases with the Python-level call.

Automerge-Triggered-By: @gvanrossum
(cherry picked from commit c53b310e5926266ce267c44a168165cacd786d6e)

Co-authored-by: scoder <stefan_ml@behnel.de>
3 files changed