This test currently takes 288 seconds to fail if output values are
wrong; there's no point to print the failure hundreds of times.
This change will exit the test early.
R=henrika@webrtc.org
BUG=623538
NOTRY=true
Review-Url: https://codereview.webrtc.org/2097363002
Cr-Commit-Position: refs/heads/master@{#13295}