Merge pull request #831 from Unity-Technologies/Fix-issue-with-instancing-and-double-sided

HDRenderPipeline: Fix issue with instancing and double sided

ScriptableRenderPipeline/HDRenderPipeline/HDRP/ShaderPass/VaryingMesh.hlsl

     float4 interpolators5 : TEXCOORD5;
 #endif
 
+    UNITY_VERTEX_INPUT_INSTANCE_ID // Must be declare before FRONT_FACE_SEMANTIC
+
-
-    UNITY_VERTEX_INPUT_INSTANCE_ID
 };
 
 // Functions to pack data to use as few interpolator as possible, the ShaderGraph should generate these functions