intel/vec4: Set up push ranges before we emit any code

intel/vec4: Set up push ranges before we emit any code

In order to avoid switching pull constants to push constants and then
having to back to pull, compute the push ranges up-front.  This way we
know by the time we emit code exactly what ranges are pushable.  This is
a bit inefficient in the case where the "normal" push constants get
compacted.  However, most apps don't use giant piles of dead uniforms
combined with substantial UBO use so this should be ok.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10571>