HasUnexpectedOutput() is evaluated two times for each test run.

This fix removes the redundant call to allow heavy text comparisons through overwriting of that method.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/17089003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15162 ce2b1a6d-e550-0410-aec6-3dcde31c8c00