in the old generation while its remembered set is being swept for
pointers into the young generation.  This is done by delaying the
copying of promoted objects from when they are first encountered and
promoted to only when their body is visited.

Review URL: http://codereview.chromium.org/115086

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1971 ce2b1a6d-e550-0410-aec6-3dcde31c8c00