The script now returns exit codes based on what occurred in the
test. Exit codes:
0 -- normal
1 -- fail/crash
88 -- warning
In addition, the scripts now handle DeviceUnresponsiveError by
returning a warning exit code overall, rather than silently moving
on.
BUG=170477, 258171
Review URL: https://chromiumcodereview.appspot.com/18323020
git-svn-id: http://src.chromium.org/svn/trunk/src/build@210749 4ff67af0-8c30-449e-8e8b-ad334ec8d88c