ci: Remove .build-rules from core test job definitions.
If you accidentally re-included your test job core definition after your
driver-specific ruleset, you'd end up running the driver job on every
source code change. This had happened with a630_gles_asan: it included
.baremetal-test-arm64-asan (and thus .baremetal-test) after including
.a630-test, to override .baremetal-test-arm64's depednencies to use asan
artifacts instead.
Acked-by: Michel Dänzer <mdaenzer@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17386>