intel/fs: Don't delete coalesced MOVs if they have a cmod
Shader-db results on ICL:
total instructions in shared programs: 17133088 -> 17133287 (<.01%)
instructions in affected programs: 61300 -> 61499 (0.32%)
helped: 0
HURT: 199This means it's likely fixing 199 bugs. :-) All the changed shaders are
in Mad Max. It's surprisingly difficult to get the back-end compiler to
generate a pattern that hits this we don't tend to emit a lot coalescable
MOVs. The pattern in Mad Max that's able to hit is fsign(fsat(x)) under
the right conditions.
Closes: #2820 (closed)