* Inlined checks for strings and regexps.
 * Rewrote split for the non-regexp case.
 * Implemented one-char case for lastIndexOf.

Review URL: http://codereview.chromium.org/596122

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3917 ce2b1a6d-e550-0410-aec6-3dcde31c8c00