nir/algebraic: Clean up value range analysis-based optimizations

nir/algebraic: Clean up value range analysis-based optimizations

Fix the a / b ordering in some compares.  Delete duplicate patterns.
Add a table explaining things.  While I was cleaning this up, I managed
to confuse myself.  The table helped sort that out.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>