The problem was continuing out of the body of a for/in (where we do
register allocation) to the loop update (where we do not).  Variables
allocated to registers where not preserved.

Review URL: http://codereview.chromium.org/53002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1585 ce2b1a6d-e550-0410-aec6-3dcde31c8c00