zts: test single-disk pool resumes properly after disk pull

A single disk pool should suspend when its disk fails and hold the IO.
When the disk is returned, the pool should return and the IO be
reissued, leaving everything in good shape.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Don Brady <don.brady@klarasystems.com>