Desugar bitwise negation into XOR and kill all UnaryOp stuff.

R=mstarzinger@chromium.org, verwaest@chromium.org

Review URL: https://codereview.chromium.org/22184004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16073 ce2b1a6d-e550-0410-aec6-3dcde31c8c00