Fix PyObject_Call() parameter names

Issue #27128: arg=>args, kw=>kwargs.

Same change for PyEval_CallObjectWithKeywords().
diff --git a/Objects/abstract.c b/Objects/abstract.c
index aaa6fc8..dcf3eb5 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2194,7 +2194,7 @@
 }
 
 PyObject *
-PyObject_Call(PyObject *func, PyObject *arg, PyObject *kw)
+PyObject_Call(PyObject *func, PyObject *args, PyObject *kwargs)
 {
     ternaryfunc call;
     PyObject *result;
@@ -2203,6 +2203,8 @@
        because it may clear it (directly or indirectly) and so the
        caller loses its exception */
     assert(!PyErr_Occurred());
+    assert(PyTuple_Check(args));
+    assert(kwargs == NULL || PyDict_Check(kwargs));
 
     call = func->ob_type->tp_call;
     if (call == NULL) {
@@ -2214,7 +2216,7 @@
     if (Py_EnterRecursiveCall(" while calling a Python object"))
         return NULL;
 
-    result = (*call)(func, arg, kw);
+    result = (*call)(func, args, kwargs);
 
     Py_LeaveRecursiveCall();