Handle all kind of arguments in the ToBooleanStub. While this is not very thrilling...

Handle all kind of arguments in the ToBooleanStub. While this is not very thrilling in itself, it is one of several steps to add type recording to this stub. Removed a duplicate check for null in the ARM stub and made a tiny simplification, removing a sub instruction.

As a side note, this change has some positive impact on the performace, e.g. imaging-darkroom is 8.3% faster and ws-ieee754conv is even 19.9% faster. No idea why the speedup is so big in some cases, but never look a gift horse in the mouth... ;-)
Review URL: http://codereview.chromium.org/7042004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7926 ce2b1a6d-e550-0410-aec6-3dcde31c8c00