That file has become a bit of the new `.gitlab-ci.yml` with just about
everything in there, but a lot of its content doesn't need to be in the
same file anymore now that `!reference` exists.
Signed-off-by: Eric Engestrom <eric@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24090>
