Move utils.h and utils.cc from runtime/vm to runtime/platform

runtime/vm/port.cc

Index: runtime/vm/port.cc
diff --git a/runtime/vm/port.cc b/runtime/vm/port.cc
index 3f5f9a384d60000cb04c1cc5b02b9f5ccfbfef1f..37413bba29e1445b91e1159acd44bc45f41c9c27 100644
--- a/runtime/vm/port.cc
+++ b/runtime/vm/port.cc
@@ -1,13 +1,13 @@
-// 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.
 
 #include "vm/port.h"
 
+#include "platform/utils.h"
 #include "vm/dart_api_impl.h"
 #include "vm/isolate.h"
 #include "vm/thread.h"
-#include "vm/utils.h"
 
 namespace dart {