Remove superfluous assert.

Remove superfluous assert.
Committed: http://code.google.com/p/v8/source/detail?r=9775

[Vyacheslav Egorov (Chromium), 2011-10-25 12:30:04]

this assert actually caught some bugs for me, so I don't think we should remove
it.

[Erik Corry, 2011-10-25 13:08:39]

There's still the almost equivalent assert at the other end of the same
function.  Do we need both?

[Vyacheslav Egorov (Chromium), 2011-10-25 13:24:10]

lgtm