test: stop all arrays before starting test.

As well a cleaning up loop devices, stop all arrays.
After all, we cannot do the one without the other.

Signed-off-by: NeilBrown <neilb@suse.com>

test

@@ -99,6 +99,7 @@ do_setup() {
   # immediately
   while grep loop /proc/partitions > /dev/null 2>&1
   do
+    mdadm -Ss
     losetup -d /dev/loop[0-9]* 2> /dev/null
     sleep 1
   done