Add test for the instance param (geometry shader)

Test/hlsl.instance.geom

@@ -0,0 +1,17 @@
+struct VertexShaderOutput
+{
+    float4 m_position : SV_POSITION;
+    float4 m_color    : COLOR0;     
+};
+
+[maxvertexcount(3)]
+[instance(5)]
+void GeometryShader(triangle VertexShaderOutput input[3], inout TriangleStream<VertexShaderOutput> output, uint id : SV_GSInstanceID)
+{
+    [loop]
+    for (int i = 0; i < 3; ++i)
+    {
+        output.Append(input[i]);
+    }
+    output.RestartStrip();
+}

gtests/Hlsl.FromFile.cpp

@@ -434,7 +434,8 @@ INSTANTIATE_TEST_SUITE_P(
         {"hlsl.typedef.frag", "PixelShaderFunction"},
         {"hlsl.whileLoop.frag", "PixelShaderFunction"},
         {"hlsl.void.frag", "PixelShaderFunction"},
-        {"hlsl.type.type.conversion.all.frag", "main"}
+        {"hlsl.type.type.conversion.all.frag", "main"},
+        {"hlsl.instance.geom", "GeometryShader"}
     }),
     FileNameAsCustomTestSuffix
 );