gitlab-ci: Test virgl driver

Add virglrenderer to the container and use the vtest transport to test
the Gallium driver. On the "host", llvmpipe is used.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4433>
6 files changed