Unrevert^2 "Derive synthetic type bounds for expressions""

Reenables https://codereview.chromium.org/17842004 (again).

R=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/18895002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15571 ce2b1a6d-e550-0410-aec6-3dcde31c8c00