Remove arguments shadow from scopes, stop rewriting parameters.

arguments/src/hydrogen.cc

Index: arguments/src/hydrogen.cc
diff --git a/arguments/src/hydrogen.cc b/arguments/src/hydrogen.cc
index 00eed04c31e36ac39dafa41f984606b9b5133598..240ea455fba227b762874da3b243d340844bc1eb 100644
--- a/arguments/src/hydrogen.cc
+++ b/arguments/src/hydrogen.cc
@@ -2294,18 +2294,13 @@ void HGraphBuilder::SetupScope(Scope* scope) {
   // Handle the arguments and arguments shadow variables specially (they do
   // not have declarations).
   if (scope->arguments() != NULL) {
-    if (!scope->arguments()->IsStackAllocated() ||
-        (scope->arguments_shadow() != NULL &&
-        !scope->arguments_shadow()->IsStackAllocated())) {
+    if (!scope->arguments()->IsStackAllocated()) {
       BAILOUT("context-allocated arguments");
     }
     HArgumentsObject* object = new HArgumentsObject;
     AddInstruction(object);
     graph()->SetArgumentsObject(object);
     environment()->Bind(scope->arguments(), object);
-    if (scope->arguments_shadow() != NULL) {
-      environment()->Bind(scope->arguments_shadow(), object);
-    }
   }
 }