bpo-37547: add _PyObject_CallMethodOneArg (GH-14685)

diff --git a/Modules/_abc.c b/Modules/_abc.c
index 219ea0d..7b5d418 100644
--- a/Modules/_abc.c
+++ b/Modules/_abc.c
@@ -480,7 +480,6 @@
 /*[clinic end generated code: output=b8b5148f63b6b56f input=a4f4525679261084]*/
 {
     PyObject *subtype, *result = NULL, *subclass = NULL;
-    PyObject *margs[2];
     _abc_data *impl = _get_impl(self);
     if (impl == NULL) {
         return NULL;
@@ -515,16 +514,12 @@
             }
         }
         /* Fall back to the subclass check. */
-        margs[0] = self;
-        margs[1] = subclass;
-        result = _PyObject_VectorcallMethodId(&PyId___subclasscheck__, margs,
-            2 | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);
+        result = _PyObject_CallMethodIdOneArg(self, &PyId___subclasscheck__,
+                                              subclass);
         goto end;
     }
-    margs[0] = self;
-    margs[1] = subclass;
-    result = _PyObject_VectorcallMethodId(&PyId___subclasscheck__, margs,
-        2 | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);
+    result = _PyObject_CallMethodIdOneArg(self, &PyId___subclasscheck__,
+                                          subclass);
     if (result == NULL) {
         goto end;
     }
@@ -536,10 +531,8 @@
         break;
     case 0:
         Py_DECREF(result);
-        margs[0] = self;
-        margs[1] = subtype;
-        result = _PyObject_VectorcallMethodId(&PyId___subclasscheck__, margs,
-            2 | PY_VECTORCALL_ARGUMENTS_OFFSET, NULL);
+        result = _PyObject_CallMethodIdOneArg(self, &PyId___subclasscheck__,
+                                              subtype);
         break;
     case 1:  // Nothing to do.
         break;
@@ -620,8 +613,8 @@
     }
 
     /* 3. Check the subclass hook. */
-    ok = _PyObject_CallMethodIdObjArgs((PyObject *)self, &PyId___subclasshook__,
-                                       subclass, NULL);
+    ok = _PyObject_CallMethodIdOneArg((PyObject *)self, &PyId___subclasshook__,
+                                      subclass);
     if (ok == NULL) {
         goto end;
     }