Update Lib/test/test_operator.py

Co-authored-by: Victor Stinner <vstinner@python.org>

Author: ashm-dev

Lib/test/test_operator.py

@@ -513,6 +513,7 @@ def return_arguments(self, *args, **kwds):
         self.assertEqual(f(a), (many_positional_arguments, many_kw_arguments))
 
     def test_methodcaller_cyclic_gc(self):
+        # gh-156762: Check for undefined behavior on calling methodcaller_clear()
         operator = self.module
 
         class C: