Merge pull request #1117 from SixLabors/optimization/branchless-block8x8-constructor

Removed unnecessary MemoryMarshal.Cast call

Author: antonfirsov

src/ImageSharp/Formats/Jpeg/Components/Block8x8.cs

@@ -35,7 +35,7 @@ internal unsafe struct Block8x8 : IEquatable<Block8x8>
         public Block8x8(Span<short> coefficients)
         {
             ref byte selfRef = ref Unsafe.As<Block8x8, byte>(ref this);
-            ref byte sourceRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<short, byte>(coefficients));
+            ref byte sourceRef = ref Unsafe.As<short, byte>(ref MemoryMarshal.GetReference(coefficients));
             Unsafe.CopyBlock(ref selfRef, ref sourceRef, Size * sizeof(short));
         }