ZTS: Fix zpool_status_008_pos false positive

Increase the injected delay to 1000ms and the ZIO_SLOW_IO_MS threshold
to 750ms to avoid false positives due to unrelated slow IOs which may
occur in the CI environment.  Additionally, clear the fault injection as
soon as it is no longer required for the test case.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#16769

tests/zfs-tests/tests/functional/cli_root/zpool_status/zpool_status_008_pos.ksh

@@ -69,15 +69,16 @@ for raid_type in "draid2:3d:6c:1s" "raidz2"; do
 	log_mustnot eval "zpool status -e $TESTPOOL2 | grep ONLINE"
 
 	# Check no ONLINE slow vdevs are show.  Then mark IOs greater than
-	# 160ms slow, delay IOs 320ms to vdev6, check slow IOs.
+	# 750ms slow, delay IOs 1000ms to vdev6, check slow IOs.
 	log_must check_vdev_state $TESTPOOL2 $TESTDIR/vdev6 "ONLINE"
 	log_mustnot eval "zpool status -es $TESTPOOL2 | grep ONLINE"
 
-	log_must set_tunable64 ZIO_SLOW_IO_MS 160
-	log_must zinject -d $TESTDIR/vdev6 -D320:100 $TESTPOOL2
+	log_must set_tunable64 ZIO_SLOW_IO_MS 750
+	log_must zinject -d $TESTDIR/vdev6 -D1000:100 $TESTPOOL2
 	log_must mkfile 1048576 /$TESTPOOL2/testfile
 	sync_pool $TESTPOOL2
 	log_must set_tunable64 ZIO_SLOW_IO_MS $OLD_SLOW_IO
+	log_must zinject -c all
 
 	# Check vdev6 slow IOs are only shown when requested with -s.
 	log_mustnot eval "zpool status -e $TESTPOOL2 | grep $TESTDIR/vdev6 | grep ONLINE"
@@ -95,10 +96,9 @@ for raid_type in "draid2:3d:6c:1s" "raidz2"; do
 	log_mustnot eval "zpool status -es $TESTPOOL2 | grep $TESTDIR/vdev2 | grep ONLINE"
 	log_mustnot eval "zpool status -es $TESTPOOL2 | grep $TESTDIR/vdev3 | grep ONLINE"
 
-	log_must zinject -c all
 	log_must zpool status -es $TESTPOOL2
 
-	zpool destroy $TESTPOOL2
+	log_must zpool destroy $TESTPOOL2
 done
 
 log_pass "Verify zpool status -e shows only unhealthy vdevs"