Avoid cloning using CloneRegExpResult for results that are just arrays.
Made a more direct path for string.match with string argument.

Review URL: http://codereview.chromium.org/1645001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4395 ce2b1a6d-e550-0410-aec6-3dcde31c8c00