code: void removeAll(final boolean mark) {
          if (mark) {
              AbstractInsnNode insn = first;
              while (insn != null) {
                  AbstractInsnNode next = insn.next;
                  insn.index = -1; // insn no longer belongs to an InsnList
                  insn.prev = null;
                  insn.next = null;
                  insn = next;
              }
          }
          size = 0;
          first = null;
          last = null;
          cache = null;
      }
docs: Removes all of the instructions of this list.
  
  @param mark
  if the instructions must be marked as no longer belonging to
  any {@link InsnList}.