radeonsi: compile non-GS middle parts of shaders immediately if enabled

radeonsi: compile non-GS middle parts of shaders immediately if enabled

Still disabled.

Only prologs & epilogs are compiled in draw calls, but each variant of those
is compiled only once per process.

VS is always compiled as hw VS.
TES is always compiled as hw VS.

LS and ES stages are always compiled on demand.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>