Move check into if statement

src/ImageSharp/Formats/Jpeg/Port/Components/ScanDecoder.cs

@@ -627,14 +627,16 @@ namespace ImageSharp.Formats.Jpeg.Port.Components
             //    if (this.bitsCount <= 0)
             //    {
             //        code = (short)this.ReadBit(stream);
-            //         this.bitsUnRead += 8;
-            //     }
             //        if (this.endOfStreamReached || this.unexpectedMarkerReached)
             //        {
             //            return -1;
             //        }
+            //
+            //        this.bitsUnRead += 8;
+            //    }
+            //
             //    this.accumulator = (this.accumulator << 8) | this.bitsData;
-            //     int lutIndex = (this.accumulator >> (this.bitsUnRead - 8)) & 0xFF;
+            //    int lutIndex = (this.accumulator >> (8 - this.bitsUnRead)) & 0xFF;
             //    int v = tree.Lookahead[lutIndex];
             //    if (v != 0)
             //    {