remove extra usinging

Author: tocsoft

tests/ImageSharp.Drawing.Tests/Processing/BaseImageOperationsExtensionTest.cs

@@ -2,8 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System.Collections.Generic;
-using System.Reflection.Metadata.Ecma335;
-using Microsoft.VisualStudio.TestPlatform.TestHost;
 using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Drawing.Processing;
 using SixLabors.ImageSharp.PixelFormats;