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.
diff --git a/Objects/complexobject.c b/Objects/complexobject.c
index 31e1278..0d391e5 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -273,7 +273,7 @@
 
     f = _PyObject_LookupSpecial(op, &PyId___complex__);
     if (f) {
-        PyObject *res = PyObject_CallFunctionObjArgs(f, NULL);
+        PyObject *res = _PyObject_CallNoArg(f);
         Py_DECREF(f);
         if (res != NULL && !PyComplex_Check(res)) {
             PyErr_SetString(PyExc_TypeError,