llvmpipe: add support for tessellation shaders

This adds the hooks between llvmpipe and draw to enable tessellation shaders.

It also updates the CI results and docs.

Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3841>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3841>