Comment 4 for bug 1394223

It's not clear to me that there's a useful difference in the output. Looking at two examples:

http://reports.vapour.ws/releases/2506/job/run-unit-tests-trusty-ppc64el/attempt/2701#highlight
http://reports.vapour.ws/releases/4031/job/run-unit-tests-centos7-amd64/attempt/952#highlight

Both say "panic: Session already closed", and seem to trace back to NewWatcher. How would a regex tell them apart?