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

从 Objects/object.c 中 _Py_NewReference 调用附近开始，检查 tracemalloc 目前如何在此处进行 hook。在确定适当的 API 层之前，阅读链接的 PR gh-115945 以及周边的 C-API 讨论。完成的标准是其他 tracer 可以注册 callback，并且 tracemalloc 使用该 API 时不会丢失 allocation trace 关联关系。