First implementation of store elimination.

BUG=
R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/100253004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20224 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Reland "No longer OOM on invalid string length."

R=ishell@chromium.org

Review URL: https://codereview.chromium.org/210683003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20225 ce2b1a6d-e550-0410-aec6-3dcde31c8c00