[Sheriff] Mark new regression test flaky on linux 32.

BUG=
TBR=jarin@chromium.org

Review URL: https://codereview.chromium.org/148483004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19000 ce2b1a6d-e550-0410-aec6-3dcde31c8c00