glsl: gather uniform dereference info before main linking loop

glsl: gather uniform dereference info before main linking loop

We want to gather information for all stages here before the main
linking loop. In the following patch we will use to information
to reduce the size of uniform arrays where possible.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4910>