ci/lava: Use init-stage2 and setup-test-env.sh from Mesa install

init-stage2.sh and setup-test-env.sh are already downloaded on the DUT as
part of the mesa-build overlay, which downloads the Mesa artifacts from
S3.

Signed-off-by: Valentine Burley <valentine.burley@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35051>

.gitlab-ci/tests/utils/test_lava_job_definition.py

@@ -62,6 +62,7 @@ def job_submitter_factory(mode: Literal["UBOOT", "FASTBOOT"], shell_file):
         mesa_job_name=mesa_job_name,
         pipeline_info=pipeline_info,
         visibility_group=visibility_group,
+        project_dir="/test_dir",
         project_name=project_name,
     )