Instead of using virtual type-tester functions we can just
generate non-virtual ones for all concrete IR classes.

This is changes reduces the V8 binary size by ~2%.

I also simplified the macros to declare new hydrogen instructions slightly.
The name used for debug output is no longer passed as a separate string.
Instead we just use the class name.
Review URL: http://codereview.chromium.org/6880014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7659 ce2b1a6d-e550-0410-aec6-3dcde31c8c00