xt/smoke/*.t should run if AUTOMATED_TESTING is set

[karenetheridge]

./Build test should also run xt/smoke/*.t tests if AUTOMATED_TESTING is set.

-   $tester->runtests(sort +find(qr/\.t$/, 't'))->has_errors and exit 1;
+   $tester->runtests(sort +find(qr/\.t$/, 't'), ( $ENV{AUTOMATED_TESTING} ? find(qr/\.t$/, 't') : () ))->has_errors and exit 1;

[Leont]

I think I've suggested such a thing before (forgot where exactly), but in a more generalized way (also for xt/{author,release,...}. I suspect it may be better if the various install tools and Dist::Zilla are in agreement on how this works, though on the other hand given MBT doesn't have configuration we ought to do something.

[Leont]

This is something we perhaps should duscuss at the toolchain summit