Replace PyObject_CallFunctionObjArgs() with fastcall

* PyObject_CallFunctionObjArgs(func, NULL) => _PyObject_CallNoArg(func)
* PyObject_CallFunctionObjArgs(func, arg, NULL) => _PyObject_CallArg1(func, arg)

PyObject_CallFunctionObjArgs() allocates 40 bytes on the C stack and requires
extra work to "parse" C arguments to build a C array of PyObject*.

_PyObject_CallNoArg() and _PyObject_CallArg1() are simpler and don't allocate
memory on the C stack.

This change is part of the fastcall project. The change on listsort() is
related to the issue #23507.

Python/import.c

@@ -985,7 +985,7 @@ get_path_importer(PyObject *path_importer_cache, PyObject *path_hooks,
         PyObject *hook = PyList_GetItem(path_hooks, j);
         if (hook == NULL)
             return NULL;
-        importer = PyObject_CallFunctionObjArgs(hook, p, NULL);
+        importer = _PyObject_CallArg1(hook, p);
         if (importer != NULL)
             break;