OptimizeInstructions: Select => and/or in more cases

[kripken]

x ? 0 : y  ==>   z & y   where z = !x

x ? y : 1  ==>   z | y   where z = !x

Only do this when we have z = !x, that is, we can invert x without adding an actual eqz. (Adding an eqz would turn this from one instruction into two, which means more work, which could be slower.)

[MaxGraey]

Will be great also add this rules:

x ? x : y   ==>   x | y
x ? y : x   ==>   x & y

x, y <- 1-bit types

however with #4161 pass it will be unnecessary

[kripken]

This is now ready for review (I updated the top comment and finished fuzzing), but not urgent.

[MaxGraey]

LGTM from my side

[MaxGraey]

@kripken could you merge this?

[kripken]

Rewritten to use a more canonicalization approach.