There was an override to fake an IDR as soon as a SPS/PPS
is encountered, but that's not valid, at least an i-slice is needed.
Amend the visl result, as the output is slightly more correct, not
duplicating frame_num.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7330>
As the visl driver does not do actual decoding but outputs a test
pattern, the fluster reference md5sums have to be changed.
This is generated using fluster's reference command and stored here to
run the v4l2 stateless codecs test against.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5434>