Expose tracemalloc hook into `_Py_NewReference` for other tracers

When new objects are created, the allocation code ends calling into _Py_NewReference (with some exceptions). tracemalloc has a hook into this function to correlate allocations and traces (that do not know anything about objects or references) with newly created objects. This happens here:

https://github.com/python/cpython/blob/3d647e70cf4fd0e7cef68ed6662de3cb2cb0d63d/Objects/object.c#L2018-L2020

This allows tracemalloc to be able to return the traceback where objects where allocated, which is great. Unfortunately other debuggers and profilers do not have this capability as there is no way to leverage trace malloc functionality or to hook into object creation.

I propose to expose an API (unclear what layer of the C-API this should be in) where callbacks can be registered to be called in _Py_NewReference and switch tracemalloc to use this API.

Linked PRs

• gh-115945

Beginne bei Objects/object.c rund um den Aufruf von _Py_NewReference und prüfe, wie tracemalloc dort derzeit eingreift. Lies den verknüpften PR gh-115945 und die umgebende C-API-Diskussion, bevor du die geeignete API-Schicht bestimmst. Als erledigt gilt die Aufgabe, wenn andere Tracer Callbacks registrieren können und tracemalloc diese API verwendet, ohne die Korrelation der Allokations-Traces zu verlieren.