iotests: 287: add qcow2 compression type test

iotests: 287: add qcow2 compression type test

The test checks fulfilling qcow2 requirements for the compression
type feature and zstd compression type operability.

Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Tested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200507082521.29210-5-dplotnikov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>