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

runtime/vm/assembler.cc

Index: runtime/vm/assembler.cc
diff --git a/runtime/vm/assembler.cc b/runtime/vm/assembler.cc
index 8319db41f9e83a0f3124a63a7abc16ff13123c1c..446c78a630fae243ffe381828c8a327a0d0b97fd 100644
--- a/runtime/vm/assembler.cc
+++ b/runtime/vm/assembler.cc
@@ -1,13 +1,14 @@
-// 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/assembler.h"
+
+#include "platform/utils.h"
 #include "vm/cpu.h"
 #include "vm/heap.h"
 #include "vm/memory_region.h"
 #include "vm/os.h"
-#include "vm/utils.h"
 #include "vm/zone.h"
 
 namespace dart {