Use tolerant comparer for .NET FX

Author: JimBobSquarePants

tests/ImageSharp.Tests/Formats/Tiff/TiffDecoderTests.cs

@@ -315,7 +315,12 @@ public void TiffDecoder_CanDecode_YCbCr_24Bit<TPixel>(TestImageProvider<TPixel>
             // converting the pixel data from Magick.NET to our format with YCbCr?
             using Image<TPixel> image = provider.GetImage();
             image.DebugSave(provider);
+
+#if NETCOREAPP
             image.CompareToReferenceOutput(ImageComparer.Exact, provider);
+#else
+            image.CompareToReferenceOutput(TolerantImageComparer.TolerantPercentage(0.0002F), provider);
+#endif
         }
 
         [Theory]