vkd3d-shader/hlsl: Support non-static unroll limits.
Enables the following pixel shader to compile:
float4 fun(uint x, uint y)
{
int i;
[unroll(x + y)]
for (i = 0; i < 8; ++i);
return float4(i, 0, 0, 0);
}
float4 main() : sv_target
{
int a = 1;
return fun(a, a);
}
Needed for the game DCS World.