Properly passing the inverse-trig.shader_test tests whose qualifiers
have been removed requires making spirv.c capable of handling ABS.
The same happens for the ps_3_0 equality test in
float-comparison.shader_test.
Tests have already been implemented in 92044d5e; this commit also reduces
the scope of some of the todos (because now they're implemented!).
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55154
