[Sheriff] Mark cpu profiler test as flaky on windows.

This is fails constantly on windows since the XP->Win7 bot upgrade.

BUG=v8:3055
R=jkummerow@chromium.org
TBR=jkummerow@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/133153006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18602 ce2b1a6d-e550-0410-aec6-3dcde31c8c00