Port a couple more stubs to x64.

runtime/vm/raw_object.cc

Index: runtime/vm/raw_object.cc
===================================================================
--- runtime/vm/raw_object.cc	(revision 3306)
+++ runtime/vm/raw_object.cc	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -165,7 +165,7 @@
   }
   ASSERT(instance_size != 0);
   intptr_t tags = ptr()->tags_;
-  ASSERT((instance_size == (SizeTag::decode(tags))) ||
+  ASSERT((instance_size == SizeTag::decode(tags)) ||
          (SizeTag::decode(tags) == 0) ||
          FreeBit::decode(tags));
   return instance_size;