tests: Test discontiguous signature masks with SM<4 shaders.

Approved-by: Elizabeth Figura (@zfigura)
Approved-by: Giovanni Mascellani (@giomasce)
Approved-by: Henri Verbeet (@hverbeet)
Merge-Request: https://gitlab.winehq.org/wine/vkd3d/-/merge_requests/1183

tests/hlsl/interface-packing.shader_test

@@ -123,3 +123,38 @@ todo probe (5, 0) rgba ( 7.0, 18.0, 19.0,  0.0)
 todo probe (6, 0) rgba (27.0, 28.0,  0.0,  0.0)
 todo probe (7, 0) rgba ( 8.0,  9.0, 10.0, 11.0)
 todo probe (8, 0) rgba (23.0, 24.0, 25.0,  0.0)
+
+[require]
+shader model >= 3.0
+
+[input layout]
+0 r32g32-float POSITION
+
+[vb 0]
+-1.0 -1.0
+-1.0 3.0
+3.0 -1.0
+
+[vertex shader]
+void main(float2 in_pos : POSITION, out float4 pos : SV_Position, out float4 color : COLOR)
+{
+    pos = float4(in_pos, 0.0f, 1.0f);
+    color = float4(1.0f, 2.0f, 3.0f, 4.0f);
+}
+
+[pixel shader]
+% The point of this test is to check that signature masks are handled correctly
+% when they are not contiguous, so we attempt reading only component .xw from
+% `color'. This happens when the shader is compiled by native, but not by us,
+% currently, so it's not very useful for the moment. I'm leaving it anyway
+% so that it either becomes useful when our HLSL compiler becomes more optimized
+% or can be eventually rewritten in assembly/bytecode when the shader runner
+% supports that.
+float4 main(float4 pos : SV_Position, float4 color : COLOR) : SV_Target
+{
+    return float4(color.x, 10.0f, 11.0f, color.w);
+}
+
+[test]
+draw triangle list 3
+todo(sm<4) probe (0, 0) rgba (1.0, 10.0, 11.0, 4.0)