get tmpfs rename to "tstile".
Note1: triggering this on any non-SMP system is not as easy (because
one system call tends to run from start to finish in one go) and
therefore I've limited it to i386 and amd64. Incidentally, I'm
still waiting for the eternally elusive MI CPU_INFO_FOREACH (or at
least something else than a stupid macro) ...
Note2: this is a "race condition" test. I tested it on my development
host and in qemu and it triggers pretty instantly. But YMMV.