BUG=v8:1669
TEST=cctest/test-heap/CollectingAllAvailableGarbageShrinksNewSpace

Review URL: http://codereview.chromium.org/8065003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9912 ce2b1a6d-e550-0410-aec6-3dcde31c8c00