gh-125447: Remove Py_TPFLAGS_HAVE_FINALIZE macro

[rruuaanng]

According to typeobj.rst

      .. deprecated:: 3.8
         This flag isn't necessary anymore, as the interpreter assumes the
         :c:member:`~PyTypeObject.tp_finalize` slot is always present in the
         type structure.

• Issue: Remove Py_TPFLAGS_HAVE_FINALIZE macro #125447

[bedevere-app]

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[rruuaanng]

In fact, I think the corresponding documents should also be deleted. Because removing Py_TPFLAGS_HAVE_FINALIZE without removing the corresponding documentation would confuse users.