Make it easier to test the UFS error handler and abort handler.

Link: https://lore.kernel.org/r/20210722033439.26550-19-bvanassche@acm.orgAcked-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>