Removed dead code: GenericUnaryOpStub is not used anymore, as a consequence, NegativeZeroHandling and UnaryOpFlags are dead, too.
Review URL: http://codereview.chromium.org/6903124

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7731 ce2b1a6d-e550-0410-aec6-3dcde31c8c00