Moved back GetRenderPipelineMaterialList to HDUtils as it's HDRP specific

ScriptableRenderPipeline/Core/CoreUtils.cs

 using System;
-using System.Collections.Generic;
-using System.Linq;
-using UnityEngine.Experimental.Rendering.HDPipeline;
 using UnityEngine.Rendering;
 using UnityEngine.Rendering.PostProcessing;
 
 
     public static class CoreUtils
     {
-        public static List<RenderPipelineMaterial> GetRenderPipelineMaterialList()
-        {
-            var baseType = typeof(RenderPipelineMaterial);
-            var assembly = baseType.Assembly;
-
-            var types = assembly.GetTypes()
-                .Where(t => t.IsSubclassOf(baseType))
-                .Select(Activator.CreateInstance)
-                .Cast<RenderPipelineMaterial>()
-                .ToList();
-
-            // Note: If there is a need for an optimization in the future of this function, user can
-            // simply fill the materialList manually by commenting the code abode and returning a
-            // custom list of materials they use in their game.
-            //
-            // return new List<RenderPipelineMaterial>
-            // {
-            //    new Lit(),
-            //    new Unlit(),
-            //    ...
-            // };
-
-            return types;
-        }
-
         // Render Target Management.
         public static void SetRenderTarget(CommandBuffer cmd, RenderTargetIdentifier buffer, ClearFlag clearFlag, Color clearColor, int miplevel = 0, CubemapFace cubemapFace = CubemapFace.Unknown)
         {

ScriptableRenderPipeline/HDRenderPipeline/Debug/DebugDisplay.cs

         {
             if (!isDebugViewMaterialInit)
             {
-                List<RenderPipelineMaterial> materialList = CoreUtils.GetRenderPipelineMaterialList();
+                List<RenderPipelineMaterial> materialList = HDUtils.GetRenderPipelineMaterialList();
 
                 // TODO: Share this code to retrieve deferred material with HDRenderPipeline
                 // Find first material that have non 0 Gbuffer count and assign it as deferredMaterial

ScriptableRenderPipeline/HDRenderPipeline/HDRenderPipeline.cs

             m_GPUCopy = new GPUCopy(asset.renderPipelineResources.copyChannelCS);
 
             // Scan material list and assign it
-            m_MaterialList = CoreUtils.GetRenderPipelineMaterialList();
+            m_MaterialList = HDUtils.GetRenderPipelineMaterialList();
             // Find first material that have non 0 Gbuffer count and assign it as deferredMaterial
             m_DeferredMaterial = null;
             foreach (var material in m_MaterialList)

ScriptableRenderPipeline/HDRenderPipeline/HDUtils.cs

+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+
+        public static List<RenderPipelineMaterial> GetRenderPipelineMaterialList()
+        {
+            var baseType = typeof(RenderPipelineMaterial);
+            var assembly = baseType.Assembly;
+
+            var types = assembly.GetTypes()
+                .Where(t => t.IsSubclassOf(baseType))
+                .Select(Activator.CreateInstance)
+                .Cast<RenderPipelineMaterial>()
+                .ToList();
+
+            // Note: If there is a need for an optimization in the future of this function, user can
+            // simply fill the materialList manually by commenting the code abode and returning a
+            // custom list of materials they use in their game.
+            //
+            // return new List<RenderPipelineMaterial>
+            // {
+            //    new Lit(),
+            //    new Unlit(),
+            //    ...
+            // };
+
+            return types;
+        }
 
         public static Matrix4x4 GetViewProjectionMatrix(Matrix4x4 worldToViewMatrix, Matrix4x4 projectionMatrix)
         {

TestbedPipelines/Fptl/SkyboxHelper.cs

 using System.Collections.Generic;
-using UnityEngine.Rendering;
-using UnityEngine.Experimental.Rendering;
 
 namespace UnityEngine.Experimental.Rendering
 {

TestbedPipelines/OnTileDeferredPipeline/OnTileDeferredRenderPipeline.cs

 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.Rendering;
-using UnityEngine.Experimental.Rendering;
-using UnityEngine.SceneManagement;
 
 namespace UnityEngine.Experimental.Rendering.OnTileDeferredRenderPipeline
 {