ci: Enable testing radeonsi's libva using libva-util unit tests.

ci: Enable testing radeonsi's libva using libva-util unit tests.

We've noticed issues with these tests when uprevving Mesa in Chrome OS.
This CI catches some existing failures, and some debug-build assertion
failures as well.

To do this, uprev deqp-runner for its new gtest-runner command.  This
runner is not as efficient as I would hope, due to some expensive code in
gtest.  I've reported the issue to gtest and it should be easily fixable,
but for now it at least means we get to use the same baseline/skip/flake
handling we have from deqp and piglit runners.

I also fixed build-libdrm for our rootfses to not throw away libdrm's
share directory, which was causing a bunch of test-time spam from radeon's
libdrm when trying to look up its marketing name tables (not that big of a
deal for deqp-runner, but really noisy for piglit and libva-utils which
make gallium screens approximatly per-test).

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13419>