nir/algebraic: add some more unop + bcsel optimizations

nir/algebraic: add some more unop + bcsel optimizations

Totals from affected shaders: (VEGA)
SGPRS: 284392 -> 284400 (0.00 %)
VGPRS: 261080 -> 261076 (-0.00 %)
Spilled SGPRs: 105 -> 105 (0.00 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Private memory VGPRs: 0 -> 0 (0.00 %)
Scratch size: 0 -> 0 (0.00 %) dwords per thread
Code Size: 24698596 -> 24277788 (-1.70 %) bytes
LDS: 196 -> 196 (0.00 %) blocks
Max Waves: 10101 -> 10105 (0.04 %)

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4830>