Parse 'super' keyword.

BUG=v8:3330
LOG=N
R=arv@chromium.org, marja@chromium.org

Review URL: https://codereview.chromium.org/480543002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23157 ce2b1a6d-e550-0410-aec6-3dcde31c8c00