Another usability issue with our TAP tests

Since "make check-world" is rather chatty, if you get a failure while
running it under high parallelism, the location of the failure has often
scrolled off the terminal window by the time all the other subjobs exit.
This is not a huge problem for tests using our traditional infrastructure,
because you can just run "git status" to look for regression.diffs files.
But a TAP test failure leaves nothing behind that git will consider
unusual. I've repeatedly had to run check-world with no parallelism
(wasting many minutes) in order to locate which test actually failed.

I'm not sure about a good way to improve this. One idea that comes
to mind is to tweak the "make check" rules so that the tmp_check
subdirectories are automatically deleted on successful completion,
but not on failure, and then remove tmp_check from the .gitignore lists.
But the trouble with that is sometimes you want to look at the test logs
afterwards, even when make thought the test succeeded.

Ideas?

regards, tom lane