Create a separate class to encapsulate ScopeInfo serialization.

Create a separate class to encapsulate ScopeInfo serialization.

The static ScopeInfo members moved into this class.
The new class is named ScopeInfoObject which I am not proud of,
better ideas are very welcome.

Also got rid of the sentinels in the serialized scope info which saves 3 words per function
and is not slower.

Review URL: http://codereview.chromium.org/2908009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5067 ce2b1a6d-e550-0410-aec6-3dcde31c8c00