`unmounted` hook of directive on teleport's child is called twice.
Version
3.0.9
Reproduction link
https://codesandbox.io/s/divine-sun-jk15p?file=/src/main.js
Steps to reproduce
Follow the link.
What is expected?
unmounted
hook is called once.
What is actually happening?
It is called twice.
The bug is introduced since v3.0.8
Please bump this up, it is a showstopper for i18n and <teleport>
use, see https://github.com/intlify/vue-i18n-next/issues/412