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

runtime/vm/virtual_memory.h

Index: runtime/vm/virtual_memory.h
diff --git a/runtime/vm/virtual_memory.h b/runtime/vm/virtual_memory.h
index 2defcdb063a29d8c29a004182d3060f9fbabb692..87070a3e7fda2475b4d3434105336e1f982b5875 100644
--- a/runtime/vm/virtual_memory.h
+++ b/runtime/vm/virtual_memory.h
@@ -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.
 
 #ifndef VM_VIRTUAL_MEMORY_H_
 #define VM_VIRTUAL_MEMORY_H_
 
+#include "platform/utils.h"
 #include "vm/globals.h"
 #include "vm/memory_region.h"
-#include "vm/utils.h"
 
 namespace dart {