Updates to maintain flag --vector-ics

Experimental feature vector-ics needs some maintenance.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/638523003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24458 ce2b1a6d-e550-0410-aec6-3dcde31c8c00