The test falkes on Windows bots as number of samples is not enough. This change increases sampling interval for the test on Windows.

BUG=2628
TBR=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/18532003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15446 ce2b1a6d-e550-0410-aec6-3dcde31c8c00