[PATCH] run-tests: skip threading for a single test (issue5040)

[timeless]

Matt Harbison wrote:
> I was a little surprised that `kill` was available on Windows.

You're actually seeing msys bash's internal kill as opposed to
kill.exe (which msys could have, but which wouldn't recognize %1 as a
meaningful argument).

I'm really not at all sure how portable this approach is. Especially
if there are lots of wrappers creating intermediate processes...

I considering trying to use ps to get parent processes, I also
considered $! [1], but then decided that %1 would work well enough.

[1] http://www.gnu.org/software/bash/manual/bashref.html#Special-Parameters