iotests: add dirty bitmap migration test

The test starts two vms (vm_a, vm_b), create dirty bitmap in
the first one, do several writes to corresponding device and
then migrate vm_a to vm_b.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20180313180320.339796-13-vsementsov@virtuozzo.com
3 files changed