Testsuite races

[Roland McGrath]

I'd like to see an enumeration of all the sets of mutually-interfering
tests and for each a mention of what files are doubly-touched, before we
settle on a solution.

My tendency is toward something that is between #2 and #3.
That is, break out common setup tasks into a shared target that
is a dependency of both test rules.

But I'd like to see all the cases first.


Thanks,
Roland