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

runtime/vm/assembler.cc

-// 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 {
 
 static uword NewContents(int capacity) {
   Zone* zone = Isolate::Current()->current_zone();
   uword result = zone->Allocate(capacity);
 #if defined(DEBUG)
   // Initialize the buffer with kBreakPointInstruction to force a break
   // point if we ever execute an uninitialized part of the code buffer.
@@ skipping 152 matching lines @@
 
 void Assembler::Unreachable(const char* message) {
   const char* format = "Unreachable: %s";
   const intptr_t len = OS::SNPrint(NULL, 0, format, message);
   char* buffer = reinterpret_cast<char*>(malloc(len + 1));
   OS::SNPrint(buffer, len + 1, format, message);
   Stop(buffer);
 }
 
 }  // namespace dart