This is one step towards a single codepath for each method in array.js.

This patch is based on rafaelw's https://codereview.chromium.org/349073002

BUG=v8:2615
LOG=Y
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/455933002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24647 ce2b1a6d-e550-0410-aec6-3dcde31c8c00