* Special case for last char in BM-match

* Patch from Erik Corry to separate BM-algoritm into special case
  functions. Also changes condition for bailing out of simple search.
* Added simple search with no bailout for very short patterns.


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@513 ce2b1a6d-e550-0410-aec6-3dcde31c8c00