vkd3d-shader/hlsl: Support lit() intrinsic.

Approved-by: Giovanni Mascellani (@giomasce)
Approved-by: Zebediah Figura (@zfigura)
Approved-by: Francisco Casas (@fcasas)
Approved-by: Henri Verbeet (@hverbeet)
Approved-by: Alexandre Julliard (@julliard)
Merge-Request: https://gitlab.winehq.org/wine/vkd3d/-/merge_requests/88

tests/lit.shader_test

@@ -0,0 +1,62 @@
+[pixel shader]
+float4 main(uniform float4 u) : sv_target
+{
+    return lit(u.x, u.y, u.z);
+}
+
+[test]
+uniform 0 float4 -0.1 10.0 0.0 0.0
+draw quad
+probe all rgba (1.0, 0.0, 0.0, 1.0)
+
+[test]
+uniform 0 float4 1.2 -0.1 0.0 0.0
+draw quad
+probe all rgba (1.0, 1.2, 0.0, 1.0)
+
+[test]
+uniform 0 float4 1.2 2.0 3.0 0.0
+draw quad
+probe all rgba (1.0, 1.2, 8.0, 1.0)
+
+[pixel shader fail]
+float4 main(uniform float4 u) : sv_target
+{
+    return lit(u.xy, u.y, u.z);
+}
+
+[pixel shader fail]
+float4 main(uniform float4 u) : sv_target
+{
+    return lit(u.x, u.xy, u.z);
+}
+
+[pixel shader fail]
+float4 main(uniform float4 u) : sv_target
+{
+    return lit(u.x, u.y, u.yz);
+}
+
+[pixel shader fail]
+uniform float4x4 m;
+
+float4 main(uniform float4 u) : sv_target
+{
+    return lit(m, u.y, u.z);
+}
+
+[pixel shader fail]
+uniform float4x4 m;
+
+float4 main(uniform float4 u) : sv_target
+{
+    return lit(u.x, m, u.z);
+}
+
+[pixel shader fail]
+uniform float4x4 m;
+
+float4 main(uniform float4 u) : sv_target
+{
+    return lit(u.x, u.y, m);
+}