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

runtime/vm/stack_frame_test.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 "include/dart_api.h"
-
-#include "vm/assert.h"
+#include "platform/assert.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/resolver.h"
 #include "vm/stack_frame.h"
 #include "vm/unit_test.h"
 #include "vm/verifier.h"
 #include "vm/zone.h"
 
@@ skipping 277 matching lines @@
       reinterpret_cast<Dart_NativeEntryResolver>(native_lookup));
   Dart_InvokeStatic(lib,
                     Dart_NewString("StackFrame2Test"),
                     Dart_NewString("testMain"),
                     0,
                     NULL);
 }
 #endif  // TARGET_ARCH_IA32 || TARGET_ARCH_X64.
 
 }  // namespace dart