The reason is that an AllocationMemento associated with an array only
lives for one gc (it is unrooted). So an excess of garbage collections
in these tests cause the Memento to be lost, and expected behavior
can't be guaranteed.

BUG=
R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/19544002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15714 ce2b1a6d-e550-0410-aec6-3dcde31c8c00