ZTS: Fix replacement/resilver_restart_001 on FreeBSD

Decrease the RESILVER_MIN_TIME_MS variable from 50 to 20.
So the test, which expects two 2 resilver starts will see them.

Logfile of the seen failures before this fix:
log: NOTE: expected 2 resilver start(s) after offline/online, found 1
log: expected 2 resilver start(s) after offline/online, found 1

The test time decreases also from around 00:42 to 00:24 seconds.

Reviewed-by: Tony Hutter <[email protected]>
Reviewed-by: Alexander Motin <[email protected]>
Signed-off-by: Tino Reichardt <[email protected]>
Closes #16822
Closes #17279

Author: mcmilk

tests/zfs-tests/tests/functional/replacement/resilver_restart_001.ksh

@@ -154,7 +154,7 @@ do
 	log_must zpool events -c
 
 	# limit scanning time
-	log_must set_tunable32 RESILVER_MIN_TIME_MS 50
+	log_must set_tunable32 RESILVER_MIN_TIME_MS 20
 
 	# initiate a resilver and suspend the scan as soon as possible
 	log_must zpool replace $TESTPOOL1 $VDEV_REPLACE