Better test case

tests/ImageSharp.Tests/Formats/WebP/Vp8EncodingTests.cs

@@ -24,15 +24,15 @@ namespace SixLabors.ImageSharp.Tests.Formats.WebP
                 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 129, 129, 129, 129, 129, 129, 129, 129,
                 129, 129, 129, 129, 129, 129, 129, 129
             };
-            short[] input = { 177, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 177, -24, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+            short[] input = { 1, 216, -48, 0, 96, -24, -48, 24, 0, -24, 24, 0, 0, 0, 0, 0, 38, -240, -72, -24, 0, -24, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
             byte[] dst = new byte[128];
             byte[] expected =
             {
-                150, 150, 150, 150, 146, 149, 152, 154, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-                0, 0, 0, 0, 150, 150, 150, 150, 146, 149, 152, 154, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-                0, 0, 0, 0, 0, 0, 0, 0, 150, 150, 150, 150, 146, 149, 152, 154, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 150, 150, 150, 150, 146, 149, 152, 154, 0, 0, 0, 0, 0, 0, 0, 0,
-                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+                161, 160, 149, 105, 78, 127, 156, 170, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                0, 0, 0, 0, 160, 160, 133, 85, 81, 129, 155, 167, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                0, 0, 0, 0, 0, 0, 0, 156, 147, 109, 76, 85, 130, 153, 163, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 152, 128, 87, 83, 88, 132, 152, 159, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
             };
             int[] scratch = new int[16];