iotests: Add filter_qtest()

The open-coded form of this filter has been copied into enough tests
that it's better to move it into iotests.py.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20250204211407.381505-15-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
5 files changed