bpo-37493: use _PyObject_CallNoArg in more places (GH-14575)

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index b848710..777e933 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -433,7 +433,7 @@
             for (i = 0; i < PyList_GET_SIZE(cpy); i++) {
                 PyObject *func, *res;
                 func = PyList_GET_ITEM(cpy, i);
-                res = PyObject_CallObject(func, NULL);
+                res = _PyObject_CallNoArg(func);
                 if (res == NULL)
                     PyErr_WriteUnraisable(func);
                 else