gh-106084: Remove _PyObject_CallMethod() function (#106159)

Remove the following private functions from the public C API:

* _Py_CheckFunctionResult()
* _PyObject_CallMethod()
* _PyObject_CallMethodId()
* _PyObject_CallMethodIdNoArgs()
* _PyObject_CallMethodIdObjArgs()
* _PyObject_CallMethodIdOneArg()
* _PyObject_MakeTpCall()
* _PyObject_VectorcallMethodId()
* _PyStack_AsDict()

Move these functions to the internal C API (pycore_call.h).

No longer export the following functions:

* _PyObject_Call()
* _PyObject_CallMethod()
* _PyObject_CallMethodId()
* _PyObject_CallMethodIdObjArgs()
* _PyObject_Call_Prepend()
* _PyObject_FastCallDictTstate()
* _PyStack_AsDict()

The following functions are still exported for stdlib shared
extensions:

* _Py_CheckFunctionResult()
* _PyObject_MakeTpCall()

Mark the following internal functions as extern:

* _PyStack_UnpackDict()
* _PyStack_UnpackDict_Free()
* _PyStack_UnpackDict_FreeNoDecRef()