glsl: Delete constant propagation pass.

glsl: Delete constant propagation pass.

freedreno results look like noise.  Excerpts:

total instructions in shared programs: 2718355 -> 2718343 (<.01%)
instructions in affected programs: 2001 -> 1989 (-0.60%)
total last-baryf in shared programs: 109960 -> 109992 (0.03%)
last-baryf in affected programs: 789 -> 821 (4.06%)
total sstall in shared programs: 198273 -> 198312 (0.02%)
sstall in affected programs: 140 -> 179 (27.86%)
total systall in shared programs: 432224 -> 432163 (-0.01%)
systall in affected programs: 241 -> 180 (-25.31%)

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21751>