suspend_resume_single: clear pool errors on fail

If the timing is unfortunate, the pool can suspend just as we're failing
because it didn't suspend. If we don't resume the pool, we hang trying
to destroy it.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes #17054

tests/zfs-tests/tests/functional/fault/suspend_resume_single.ksh

@@ -30,6 +30,7 @@ DATAFILE="$TMPDIR/datafile"
 
 function cleanup
 {
+	zpool clear $TESTPOOL
 	destroy_pool $TESTPOOL
 	unload_scsi_debug
 	rm -f $DATA_FILE