Store both major and minor key on code stubs.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/409613002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22505 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Small improvement to String.fromCodePoint.

R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/390173004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22506 ce2b1a6d-e550-0410-aec6-3dcde31c8c00