Deferring side effecting code in `_Py_Dealloc()`

Currently _Py_Dealloc() can call arbitrary code, and since _Py_Dealloc() can be called by any Py_DECREF() is means that Py_DECREF() can call arbitrary code. Py_DECREF() is everywhere, so it impairs our ability to reason about about the behavior of code.
This problem is not as severe as https://github.com/python/cpython/issues/97922, but is still worth fixing, especially as it will impair our ability to optimize traces for 3.12.

We can either make a Py_SAFE_DECREF() to be used internally, or change Py_DECREF() to defer all potentially side-effecting deallocation functions.

It is not clear which is the best option. Changing Py_DECREF() is simple, and certainly easy to reason about, but might delay deallocation of extension module objects for too long.

Inizia esaminando gli entry point _Py_Dealloc() e Py_DECREF() citati in questa issue, quindi leggi la issue 97922 per il contesto correlato. Confronta l’approccio proposto con Py_SAFE_DECREF() con la modifica di Py_DECREF() stesso, incluso l’effetto sulla deallocazione degli oggetti dei moduli di estensione. Il lavoro è completato quando viene selezionato e implementato un design giustificato, con una copertura del comportamento di deallocazione risultante.