Fix assertion failure introduced by my previous change.

Review URL: http://codereview.chromium.org/6621068

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7087 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

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);
   }