Regularly print output in the test farm tests (#7079)
Regularly print output in the test farm tests (#7079)

* Occasionally print output in test farm tests.

* Flush output.

stweil/letsencrypt,lmcro/letsencrypt,letsencrypt/letsencrypt,stweil/letsencrypt,lmcro/letsencrypt,letsencrypt/letsencrypt