nir/algebraic: add scmp algebraic optimizations

When 'x' is the result of a scmp op:

x != 0.0 or x == 1.0: passthrough
x == 0.0 or x != 1.0: invert

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Matt Turner <mattst88@gmail.com>
13 jobs for !1151 with nir-algebraic-opts in 10 minutes and 27 seconds (queued for 2 seconds)
merge request