function rightLeftRotation(node) {
  rightRotation(node.right);
  return leftRotation(node);
}
Right Left Rotation (RL Rotation)

@example RL rotation on 1

  1*                           1*
   \                            \                          2
     3   -right-rotation(3)->    2   -left-rotation(1)->  /  \
   /                              \                      1*   3
  2                                3

@param {TreeNode} node
@returns {TreeNode} new parent after the rotation