Just initialize elements pointer in fast literal when pre-tenuring.

BUG=
R=ishell@chromium.org

Review URL: https://codereview.chromium.org/148253004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19056 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Remake of the load elimination fix made earlier (r18884).

R=titzer@chromium.org, verwaest@chromium.org

Review URL: https://codereview.chromium.org/149063010

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19057 ce2b1a6d-e550-0410-aec6-3dcde31c8c00