With crankshaft, a code object can change its optimizability: it can start as
optimizable code object, but later we can find out it was a bad idea to
optimize it.  Alas, currently we don't have a proper event to communicate
this back to logger.  Hence we temporary allow a code object to be viewed
as optimizable judging from logs while being unoptimizable judging from
heap traversal.

Review URL: http://codereview.chromium.org/6250054

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6553 ce2b1a6d-e550-0410-aec6-3dcde31c8c00