Prohibit serializing with --harmony-scoping.

R=jochen@chromium.org
BUG=v8:3628
LOG=N

Review URL: https://codereview.chromium.org/650423005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24686 ce2b1a6d-e550-0410-aec6-3dcde31c8c00