fixes bug 997236 - Run check.py on ALL files before exiting (DO NOT MERGE YET)

@lonnen r?

This first comment has some deliberate errors added just to see if the new change to jenkins-test.sh catches it accordingly. 

Once leeroy is happy I'll commit one more to this PR. 

NB: We currently don't have a strict jshint policy on .js files. That's unfortunate. I filed a couple of followup bugs to improve that. Once that's in place, we can some day uncomment the checking of the `.js` extension.