vkd3d-shader/hlsl: Support case-insensitive lookup for builtin 'dword' type.

Approved-by: Zebediah Figura (@zfigura)
Approved-by: Giovanni Mascellani (@giomasce)
Approved-by: Henri Verbeet (@hverbeet)
Approved-by: Alexandre Julliard (@julliard)
Merge-Request: https://gitlab.winehq.org/wine/vkd3d/-/merge_requests/101

tests/hlsl-type-names.shader_test

@@ -0,0 +1,44 @@
+[pixel shader]
+typedef float2 Dword;
+typedef float3 dWord;
+
+float4 f()
+{
+    typedef Dword dword;
+    dword v1 = {1, 2};
+    DWORD v4 = 4;
+    return float4(v1.x, v1.y, 3, v4);
+}
+
+float4 f2()
+{
+    typedef dword dword;
+    dword v = 1;
+    return float4(v, v, v, v);
+}
+
+float4 main() : SV_TARGET
+{
+    return f() + f2();
+}
+
+[test]
+draw quad
+probe all rgba (2.0, 3.0, 4.0, 5.0)
+
+% The "dword" alias is pre-defined as lowercase
+[pixel shader fail]
+typedef float2 dword;
+
+float4 main() : sv_target
+{
+    return float4(0, 0, 0, 0);
+}
+
+[pixel shader fail]
+struct DWORD s;
+
+float4 main() : sv_target
+{
+    return float4(0, 0, 0, 0);
+}