tests/qemu-iotests: add case to write compressed data of multiple clusters

tests/qemu-iotests: add case to write compressed data of multiple clusters

Add the case to the iotest #214 that checks possibility of writing
compressed data of more than one cluster size. The test case involves
the compress filter driver showing a sample usage of that.

Signed-off-by: Andrey Shinkevich <[email protected]>
Reviewed-by: Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by: Max Reitz <[email protected]>
Message-id: 1575288906[email protected]
Signed-off-by: Max Reitz <[email protected]>