Parsing some kinds of integers and junk values in Runtime_NumberToString. For that values the string is converted into int and then into SMI. It lets to avoid floating point operations.

Review URL: http://codereview.chromium.org/1572004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4331 ce2b1a6d-e550-0410-aec6-3dcde31c8c00