rm -rf and then copying over all the contents again is a waste of time
when we'll almost always be using the same rootfs. Saves about 30s of job
time.
Closes: #3065
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5266>
Using arm_test-base as a separate base layer as well for storage &
network bandwidth efficiency.
Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5381>