GPU Instancing work on LWRP shadergraph shaders

-Fixed placement of main passes instancing setup
-Added missing stereo instancing macros
-Added missing fragment Instancing ID for future work in shadow/depth passes

com.unity.render-pipelines.lightweight/LWRP/Editor/ShaderGraph/LightWeightPBRSubShader.cs

 
                 foreach (var channel in vertexRequirements.requiresMeshUVs.Distinct())
                     vertexDescriptionInputStruct.AppendLine("half4 {0};", channel.GetUVName());
+
+                vertexDescriptionInputStruct.AppendLine("UNITY_VERTEX_INPUT_INSTANCE_ID");
             }
 
             // -------------------------------------

com.unity.render-pipelines.lightweight/LWRP/Editor/ShaderGraph/lightweightPBRExtraPasses.template

 	{
 	    float2 uv           : TEXCOORD0;
 	    float4 clipPos      : SV_POSITION;
+        UNITY_VERTEX_INPUT_INSTANCE_ID
+        UNITY_VERTEX_OUTPUT_STEREO
 	};
 
     // x: global clip space bias, y: normal world space bias
 	{
 	    VertexOutput o;
 	    UNITY_SETUP_INSTANCE_ID(v);
+        UNITY_TRANSFER_INSTANCE_ID(v, o);
+        UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
 
         // Vertex transformations performed by graph
 ${VertexShader}
 	    return o;
 	}
 
-    half4 ShadowPassFragment() : SV_TARGET
+    half4 ShadowPassFragment(VertexOutput IN) : SV_TARGET
+        UNITY_SETUP_INSTANCE_ID(IN);
         return 0;
     }
 
 	{
 	    float2 uv           : TEXCOORD0;
 	    float4 clipPos      : SV_POSITION;
+        UNITY_VERTEX_INPUT_INSTANCE_ID
+        UNITY_VERTEX_OUTPUT_STEREO
 	};
 
     VertexOutput vert(GraphVertexInput v)
+        UNITY_TRANSFER_INSTANCE_ID(v, o);
+        UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
 
 	    // Vertex transformations performed by graph
 ${VertexShader}
 	    return o;
     }
 
-    half4 frag() : SV_TARGET
+    half4 frag(VertexOutput IN) : SV_TARGET
+        UNITY_SETUP_INSTANCE_ID(IN);
         return 0;
     }
     ENDHLSL

com.unity.render-pipelines.lightweight/LWRP/Editor/ShaderGraph/lightweightPBRForwardPass.template

 		// Interpolators defined by graph
 ${VertexOutputStruct}
         UNITY_VERTEX_INPUT_INSTANCE_ID
+    	UNITY_VERTEX_OUTPUT_STEREO
+		GraphVertexOutput o = (GraphVertexOutput)0;
+        UNITY_SETUP_INSTANCE_ID(v);
+    	UNITY_TRANSFER_INSTANCE_ID(v, o);
+		UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
+
 		// Vertex transformations performed by graph
 ${VertexShader}
 		VertexDescriptionInputs vdi = (VertexDescriptionInputs)0;
 	    VertexDescription vd = PopulateVertexData(vdi);
 		v.vertex.xyz = vd.Position;
-
-        GraphVertexOutput o = (GraphVertexOutput)0;
-
-        UNITY_SETUP_INSTANCE_ID(v);
-    	UNITY_TRANSFER_INSTANCE_ID(v, o);
 
 		// Vertex shader outputs defined by graph
 ${VertexShaderOutputs}

com.unity.render-pipelines.lightweight/LWRP/Editor/ShaderGraph/lightweightUnlitExtraPasses.template

     {
         float2 uv           : TEXCOORD0;
         float4 clipPos      : SV_POSITION;
+        UNITY_VERTEX_INPUT_INSTANCE_ID
+        UNITY_VERTEX_OUTPUT_STEREO
     };
 
     // x: global clip space bias, y: normal world space bias
     {
         VertexOutput o;
         UNITY_SETUP_INSTANCE_ID(v);
+        UNITY_TRANSFER_INSTANCE_ID(v, o);
+        UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
 
         // Vertex transformations performed by graph
 ${VertexShader}
         return o;
     }
 
-    half4 ShadowPassFragment() : SV_TARGET
+    half4 ShadowPassFragment(VertexOutput IN) : SV_TARGET
+        UNITY_SETUP_INSTANCE_ID(IN);
         return 0;
     }
 
     {
         float2 uv           : TEXCOORD0;
         float4 clipPos      : SV_POSITION;
+        UNITY_VERTEX_INPUT_INSTANCE_ID
+        UNITY_VERTEX_OUTPUT_STEREO
     };
 
     VertexOutput vert(GraphVertexInput v)
+        UNITY_TRANSFER_INSTANCE_ID(v, o);
+        UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
 
         // Vertex transformations performed by graph
 ${VertexShader}
         return o;
     }
 
-    half4 frag() : SV_TARGET
+    half4 frag(VertexOutput IN) : SV_TARGET
+        UNITY_SETUP_INSTANCE_ID(IN);
         return 0;
     }
     ENDHLSL

com.unity.render-pipelines.lightweight/LWRP/Editor/ShaderGraph/lightweightUnlitPass.template

         // Interpolators defined by graph
 ${VertexOutputStruct}
         UNITY_VERTEX_INPUT_INSTANCE_ID
+        UNITY_VERTEX_OUTPUT_STEREO
+        GraphVertexOutput o = (GraphVertexOutput)0;
+        UNITY_SETUP_INSTANCE_ID(v);
+        UNITY_TRANSFER_INSTANCE_ID(v, o);
+        UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
+
         // Vertex transformations performed by graph
 ${VertexShader}
         VertexDescriptionInputs vdi = (VertexDescriptionInputs)0;
         VertexDescription vd = PopulateVertexData(vdi);
         v.vertex.xyz = vd.Position;
-        
-        GraphVertexOutput o = (GraphVertexOutput)0;
-        
-        UNITY_SETUP_INSTANCE_ID(v);
-        UNITY_TRANSFER_INSTANCE_ID(v, o);
 
         o.position = TransformObjectToHClip(v.vertex.xyz);
         // Vertex shader outputs defined by graph