The following unary identities are applied:
||x|| -> |x|
|-x| -> |x|
~(~x) -> x
f(g(x)) -> g(x), where f(), g() are floor() or ceil() functions.
-(-x) -> x
!!x -> x
!(x == y) -> x != y, !(x < y) -> x >= y, etc (for integers).
This is simply unnecessary and wastes time.
As part of this, simply remove the "all" directive. Only for a couple of tests
is it even potentially interesting to validate all pixels (e.g.
nointerpolation.shader_test), and for those "all" is replaced with an explicit
(0, 0, 640, 480) rect.
In all other cases we just probe (0, 0).
