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

runtime/vm/flags.cc

Index: runtime/vm/flags.cc
diff --git a/runtime/vm/flags.cc b/runtime/vm/flags.cc
index 584731f6a708b8cffb9d1bcfb4895af73e32040c..ef3c7187b53a9e9a7264e48effb2e18e2c373b9f 100644
--- a/runtime/vm/flags.cc
+++ b/runtime/vm/flags.cc
@@ -1,10 +1,10 @@
-// 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/flags.h"
 
-#include "vm/assert.h"
+#include "platform/assert.h"
 #include "vm/os.h"
 
 namespace dart {