Add more bailouts for Array.slice over arguments.

Add more bailouts for Array.slice over arguments.

Unfortunately, arguments is pretty much the normal JS object.  For now
I am adding more sanity checks (in hope that typically arguments
list is rather short.)  However it probably requires more systematic
treatment, for example, we could optimistically copy elements until
we meet first hole and in this case resort to JS builtin.

Committed: http://code.google.com/p/v8/source/detail?r=6256

[antonm, 2010-12-31 11:26:52]

Mads,

may you have a look?

Another option would be to revert r6085.  I'll send you performance number
somewhat later, but if they reasonable, I'd rather commit this version than roll
back r6085.

[Mads Ager (chromium), 2011-01-04 09:06:55]

LGTM