re-enable integrityhuge test

We disabled it at the time because it would deadlock in some cases
(though not on my machine).

Since then, some deadlock fixes have accumulated. I don't know whether
the culprit has been found and remedied, but it doesn't hurt to try. If
it turns out to still be a problem, we can always disable them again
afterwards.

While here, remove generated files ("missing") from git.