Remove unused ValueInfo struct

BUG=
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/46673004

Patch from Adrian Perez de Castro <aperez@igalia.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17577 ce2b1a6d-e550-0410-aec6-3dcde31c8c00