Make PreviewProperty check a bit nicer and fix a warning

ShaderGraph/com.unity.shadergraph/Editor/Data/Graphs/PreviewProperty.cs

 
         public void SetMaterialPropertyBlockValue(MaterialPropertyBlock block)
         {
-            if (propType == PropertyType.Texture && textureValue != null || propType == PropertyType.Texture2DArray && textureValue != null || propType == PropertyType.Texture3D && textureValue != null)
+            if ((propType == PropertyType.Texture || propType == PropertyType.Texture2DArray || propType == PropertyType.Texture3D) && textureValue != null)
                 block.SetTexture(name, m_Data.textureValue);
             else if (propType == PropertyType.Cubemap && cubemapValue != null)
                 block.SetTexture(name, m_Data.cubemapValue);

ShaderGraph/com.unity.shadergraph/Editor/Data/Util/GraphUtil.cs

 using UnityEditor.Graphing.Util;
 using UnityEngine;
 using System.Reflection;
-using System.Text.RegularExpressions;
 
 namespace UnityEditor.ShaderGraph
 {