repro: loop in watch stop

[cexbrayat]

The commit setups a component which is just:

• displaying a price
• recording price changes with a watcher
• after 3 seconds we stop recording by calling the WatchStopHandle returned by watchEffect

In rc.4 this works fine.
In rc.5, it goes into a recursive loop.

  setup() {
    const price = ref(10);

    const history = ref<Array<string>>([]);
    const stopRecording = watchEffect(() => {
      history.value.push(`Price changed to ${price.value}`);
    });

    // stop recording after 3 seconds
    setTimeout(() => {
      stopRecording();
    }, 3000);

    return { price, history };
  }