Reduces size of preparser data significantly when there are nested functions.
Also allows us to drop the "skip" fields of function entries,
that tells us how much preparse-data to skip when skipping the function source.

Review URL: http://codereview.chromium.org/3412034

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5541 ce2b1a6d-e550-0410-aec6-3dcde31c8c00