Await blocks with no dynamic content behave incorrectly

[Rich-Harris]

REPL. When you click the button, a new block is created; the old one reverts to its pending state and stays in the DOM.

<button on:click='updatePromise()'>click me</button>

{#await promise}
  <p>loading...</p>
{:then value}
  <p>loaded</p> <!-- change this to `loaded {value}` and it works correctly -->
{:catch error}
  <p>errored</p>
{/await}

<script>
  export default {
    data: () => ({
      promise: new Promise(f => setTimeout(() => f(42), 1000))
    }),
		
    methods: {
      updatePromise() {
        this.set({
          promise: new Promise(f => setTimeout(() => f(99), 1000))
        });
      }
    }
  };
</script>