test/sq-poll-kthread: include grace period before thread check
test/sq-poll-kthread: include grace period before thread check

Files can be put async, which means that it may very well be that the
thread is alive the instant after io_uring_queue_exit() has returned.
Add a 1 second grace period before checking, hopefully that's enough
to remove false positives from this test.

Signed-off-by: Jens Axboe <cd8c6775e60d6f67a6984377324e5290df3d5358@kernel.dk>

axboe/liburing,axboe/liburing,axboe/liburing