[Sheriff] Skip failing test on nacl.

TBR=danno@chromium.org
BUG=v8:2998

Review URL: https://codereview.chromium.org/68163012

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17637 ce2b1a6d-e550-0410-aec6-3dcde31c8c00