code: static Node computeFallThrough(Node n) {
      switch (n.getToken()) {
        case DO:
        case FOR:
          return computeFallThrough(n.getFirstChild());
        case FOR_IN:
        case FOR_OF:
        case FOR_AWAIT_OF:
          return n.getSecondChild();
        case LABEL:
          return computeFallThrough(n.getLastChild());
        default:
          return n;
      }
    }
docs: Computes the destination node of n when we want to fallthrough into the
  subtree of n. We don't always create a CFG edge into n itself because of
  DOs and FORs.