Move assert.h/assert.cc from runtime/vm to runtime/platform

runtime/vm/scanner.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/scanner.h"
 
-#include "vm/assert.h"
+#include "platform/assert.h"
 #include "vm/flags.h"
 #include "vm/object.h"
 #include "vm/thread.h"
 #include "vm/token.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_tokens, false, "Print scanned tokens.");
 
 void Scanner::InitKeywordTable() {
@@ skipping 827 matching lines @@
               "%c%"PRIxPTR, kPrivateKeySeparator, key_value);
   const String& result = String::Handle(String::New(private_key));
   return result.raw();
 }
 
 
 void Scanner::InitOnce() {
 }
 
 }  // namespace dart