Don't use BitConverter

Since `BitConverter.IsLittleEndian` changes on a per-system basis, we
should just put a little endian implementation in play. Now the values
are always deterministic on all systems.

Author: jonathanpeppers

src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/CRC64.cs

@@ -151,6 +151,15 @@ protected override void HashCore (byte [] array, int ibStart, int cbSize)
 			}
 		}
 
-		protected override byte [] HashFinal () => BitConverter.GetBytes (crc);
+		protected override byte [] HashFinal ()
+		{
+			// Equivalent to BitConverter.GetBytes(crc), but *always* little endian
+			const int length = 8;
+			byte [] bytes = new byte [length];
+			for (int index = 0; index < length; index++) {
+				bytes [index] = (byte) (crc >> (8 * index) & 0xFF);
+			}
+			return bytes;
+		}
 	}
 }