Handle octal escapes in everything but RegExps.
Extend preparser test suite to test whether the preparser reports
exceptions to throw.

TEST=preparser/*

Review URL: http://codereview.chromium.org/6927075

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7804 ce2b1a6d-e550-0410-aec6-3dcde31c8c00