ci/llvmpipe: reenable gpu shader5 tests

I hadn't realised these were disabled, llvmpipe now exposes this extension.

One additional failure is fine to get the added testing coverage.

Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5973>
2 files changed