make check-world output

There was some recent discussion about making "make check-world" faster.
I'm all for that, but how about making it quieter? On both machines I've
run it on (CentOS6.8 and Ubuntu 16.04.2), it dumps some gibberish to
stderr, example attached. Which first made me wonder whether the test
passed or failed, and then made me give up on running it altogether when I
couldn't easily figure that out. Am I supposed to be seeing this? Am I
supposed to understand it?

Also, it runs in about 8 minutes, not the 20 minutes reported by others.
My system is virtualized, and not particularly fast. I wonder if it is
failing early somewhere without running to completion? How would/should I
know?

Cheers,

Jeff