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

runtime/vm/virtual_memory.h

-// 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 {
 
 class VirtualMemory {
  public:
   // The reserved memory is unmapped on destruction.
   ~VirtualMemory();
 
   uword start() const { return region_.start(); }
   uword end() const { return region_.end(); }
@@ skipping 53 matching lines @@
   void* reserved_pointer_;
 
   static uword page_size_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VirtualMemory);
 };
 
 }  // namespace dart
 
 #endif  // VM_VIRTUAL_MEMORY_H_