Allow for no samples in test-cpu-profiler/SampleWhenFrameIsNotSetup

The test should only check that there are no sample stacks that never possible in the JS code being profiled.

BUG=v8:2628
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/14845018

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14723 ce2b1a6d-e550-0410-aec6-3dcde31c8c00