[Isolates] Merge (7083,7111] from bleeding_edge.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 3201f5d2a2e48416c7bb9cac633ce54b72119fcc..4c678e4517613892b3406d1bf9d780d41eaca7f4 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -414,10 +414,7 @@ bool HValue::UpdateInferredType() {
 void HValue::RegisterUse(int index, HValue* new_value) {
   HValue* old_value = OperandAt(index);
   if (old_value == new_value) return;
-  if (old_value != NULL) {
-    ASSERT(old_value->uses_.Contains(this));
-    old_value->uses_.RemoveElement(this);
-  }
+  if (old_value != NULL) old_value->uses_.RemoveElement(this);
   if (new_value != NULL) {
     new_value->uses_.Add(this);
   }