run-tests: report tests as failed when run-test raises an error
Before no message was returned to the main thread. No result was registered
and no new thread was started.
This does not happen when running normal. But when fiddling around with
the test infrastructure, this helps a lot.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ echo 'base' > base
$ hg ci -Ambase
adding base
$ hg qnew -mmqbase mqbase
$ hg qsave
$ hg qrestore 2
restoring status: hg patches saved state