tracie: Make tests independent of environment

Provide some sensible values for required environment variables to allow
tests to run properly in any environment.

Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6598>
2 files changed