tests/qemu-iotests: Fix test 033 for running with non-file protocols

tests/qemu-iotests: Fix test 033 for running with non-file protocols

When running iotest 033 with the ssh protocol, it fails with:

 033   fail       [14:48:31] [14:48:41]   10.2s                output mismatch
 --- /.../tests/qemu-iotests/033.out
 +++ /.../tests/qemu-iotests/scratch/qcow2-ssh-033/033.out.bad
 @@ -174,6 +174,7 @@
  512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
  wrote 512/512 bytes at offset 2097152
  512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 +qemu-io: warning: Failed to truncate the tail of the image: ssh driver does not support shrinking files
  read 512/512 bytes at offset 0
  512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

We already check for the qcow2 format here, so let's simply also
add a check for the protocol here, too, to only test the truncation
with the file protocol.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240315111108.153201-2-thuth@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>