gitlab-ci: Switch LAVA jobs to use shared dEQP runner

gitlab-ci: Switch LAVA jobs to use shared dEQP runner

Take one step towards sharing code between the LAVA and non-LAVA jobs,
with the goals of reducing maintenance burden and use of computational
resources.

The env var DEQP_NO_SAVE_RESULTS allows us to skip the procesing of the
XML result files, which can take a long time and is not useful in the
LAVA case as we are not uploading artifacts anywhere at the moment.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Eric Anholt <eric@anholt.net>