glsl: Remove CSE pass.

glsl: Remove CSE pass.

With NIR, it actually hurts things.

total instructions in shared programs: 6529329 -> 6528888 (-0.01%)
instructions in affected programs:     14833 -> 14392 (-2.97%)
helped:                                299
HURT:                                  1

In all affected programs I inspected (including the single hurt one) the
pass CSE'd some multiplies and caused some reassociation (e.g., caused
(A * B) * C to be A * (B * C)) when the original intermediate result was
reused elsewhere.

Acked-by: Kenneth Graunke <kenneth@whitecape.org>