The IC records the set of types it has seen, e.g. {String} or {Boolean,
Undefined}, etc.  Note that in theory this could lead to a large number of
different ToBoolean ICs (512, to be exact, because we distinguish 9 types),
but in practice only a small handful of them are actually generated.

Currently the type recording part is only implemented on ia32, other platforms
continue to work like they did before, though.

Removed some dead code on the way.
Review URL: http://codereview.chromium.org/7473028

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8716 ce2b1a6d-e550-0410-aec6-3dcde31c8c00