intel/fs/xehp: Merge repeated in-order read dependencies instead of replacement.

intel/fs/xehp: Merge repeated in-order read dependencies instead of replacement.

Previously the software scoreboard structure would drop previous
dependencies for a given register and replace them with the most
recent one for the same register when a new instruction (or set of
instructions) is processed.  This worked correctly on the Gfx12LP
platforms this code was originally designed for, because a repeated
dependency on the same register would either require the second
instruction to synchronize against the first (so the first dependency
could be disregarded from that point on) *or* require the dependency
to be RaR and in-order, which allows the synchronization to be
optimized out (the first dependency could still be disregarded as
well, since the pipeline is in-order).  However the latter assumption
will break on upcoming Gfx12HP platforms, because they have multiple
asynchronous FPU pipelines, so whenever we hit a RaR dependency we
need to propagate forward both dependencies, since the order in which
both reads will complete is not guaranteed by the hardware in cases
where they occur from different asynchronous pipelines.

Note that this dependency propagation change requires us to change the
definition of dependency::done as well, since that constant is defined
to discard any previous dependency information when used as argument
for shadow().

This has been reported to fix the following conformance failures on DG2:

   KHR-GL46.shaders.uniform_block.random.all_per_block_buffers.19
   dEQP-GLES3.functional.shaders.derivate.fwidth.*

Reported-by: Tapani Pälli <tapani.palli@intel.com>
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/5670
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14273>