Revert "[Sheriff] Mark profviz flaky on GC stress."

This reverts commit f70687c1e5ef15254887e0619939e25a834e936e.

BUG=
R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/148493006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18977 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Once again: Fixed some lifetime/ownership issues in cctest

   * Fixed lifetime issue in cctest/test-heap-profiler/HeapSnapshotJSONSerialization.

   * Fixed ownership issue in cctest/test-api/ContainsOnlyOneByte.

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/142553005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18978 ce2b1a6d-e550-0410-aec6-3dcde31c8c00