gh-128863: Deprecate private C API functions (#128864)

Deprecate private C API functions:

* _PyBytes_Join()
* _PyDict_GetItemStringWithError()
* _PyDict_Pop()
* _PyThreadState_UncheckedGet()
* _PyUnicode_AsString()
* _Py_HashPointer()
* _Py_fopen_obj()

Replace _Py_HashPointer() with Py_HashPointer().

Remove references to deprecated functions.

Objects/descrobject.c

@@ -1349,7 +1349,7 @@ wrapper_hash(PyObject *self)
     wrapperobject *wp = (wrapperobject *)self;
     Py_hash_t x, y;
     x = PyObject_GenericHash(wp->self);
-    y = _Py_HashPointer(wp->descr);
+    y = Py_HashPointer(wp->descr);
     x = x ^ y;
     if (x == -1)
         x = -2;

Objects/dictobject.c

@@ -3090,8 +3090,8 @@ PyDict_PopString(PyObject *op, const char *key, PyObject **result)
 }
 
 
-PyObject *
-_PyDict_Pop(PyObject *dict, PyObject *key, PyObject *default_value)
+static PyObject *
+dict_pop_default(PyObject *dict, PyObject *key, PyObject *default_value)
 {
     PyObject *result;
     if (PyDict_Pop(dict, key, &result) == 0) {
@@ -3104,6 +3104,12 @@ _PyDict_Pop(PyObject *dict, PyObject *key, PyObject *default_value)
     return result;
 }
 
+PyObject *
+_PyDict_Pop(PyObject *dict, PyObject *key, PyObject *default_value)
+{
+    return dict_pop_default(dict, key, default_value);
+}
+
 static PyDictObject *
 dict_dict_fromkeys(PyInterpreterState *interp, PyDictObject *mp,
                    PyObject *iterable, PyObject *value)
@@ -4465,7 +4471,7 @@ static PyObject *
 dict_pop_impl(PyDictObject *self, PyObject *key, PyObject *default_value)
 /*[clinic end generated code: output=3abb47b89f24c21c input=e221baa01044c44c]*/
 {
-    return _PyDict_Pop((PyObject*)self, key, default_value);
+    return dict_pop_default((PyObject*)self, key, default_value);
 }
 
 /*[clinic input]

Objects/methodobject.c

@@ -331,7 +331,7 @@ meth_hash(PyObject *self)
 {
     PyCFunctionObject *a = _PyCFunctionObject_CAST(self);
     Py_hash_t x = PyObject_GenericHash(a->m_self);
-    Py_hash_t y = _Py_HashPointer((void*)(a->m_ml->ml_meth));
+    Py_hash_t y = Py_HashPointer((void*)(a->m_ml->ml_meth));
     x ^= y;
     if (x == -1) {
         x = -2;

Objects/odictobject.c

@@ -260,7 +260,7 @@ mp_length         __len__          -                   dict_length
 mp_subscript      __getitem__      -                   dict_subscript
 mp_ass_subscript  __setitem__      -                   dict_ass_sub
                   __delitem__
-tp_hash           __hash__         _Py_HashPointer     ..._HashNotImpl
+tp_hash           __hash__         Py_HashPointer      ..._HashNotImpl
 tp_str            __str__          object_str          -
 tp_getattro       __getattribute__ ..._GenericGetAttr  (repeated)
                   __getattr__