travis builds do not report phpunit failures/errors anymore

This seems to be a recent regression caused by MDL-66322

Uh, oh... I think I've detected a regression of this.

1) Do any tiny change forcing a unit test to fail (change 1 assertion, throw an exception...).
2) Push to github and get travis testing it.
3a) Expected result: the PHPUNIT jobs fails.
3b) Current result: The PHPUNIT jobs end ok.

Real example, I've a branch automatically run weekly, and known to be failing... and suddenly I got a mail from travis it had passed, I could not believe it! Looking to the logs you'll see it fails, errors... and not mater of that... it passes!

Link: https://travis-ci.org/github/stronk7/moodle/builds/707981008

Surely it's because the new line added after the phpunit execution "eats" its exit code, we need to fix that ASAP.