Refactor instructions

Author: Seggan

src/main/java/io/github/seggan/javaclasslib/attributes/code/instructions/CPInstruction.java

@@ -11,4 +11,7 @@ protected JvmInstruction(int instructionByte) {
     public byte getInstructionByte() {
         return instructionByte;
     }
+    public byte[] getInstructionBytes() {
+        return new byte[]{instructionByte};
+    }
 }