Missed one of Benedikt's requested changes

Author: StanFromIreland

Lib/test/test_heapq.py

@@ -111,9 +111,9 @@ def check_invariant(self, heap):
                 self.assertTrue(heap[parentpos] <= item)
 
     def check_max_invariant(self, heap):
-        for pos in range(1, len(heap)):
+        for pos, item in enumerate(heap[1:], start=1):
             parentpos = (pos - 1) >> 1
-            self.assertGreaterEqual(heap[parentpos], heap[pos])
+            self.assertGreaterEqual(heap[parentpos], item)
 
     def test_heapify(self):
         for size in list(range(30)) + [20000]: