actions and attachments don't work in async components

[ottomated]

Describe the bug

All attachments and actions are broken in any component with an await in its script block. They don't get called immediately and I'm unable to reproduce when they eventually do get called.

This reproduces it, and commenting out the promise works.

<script>
  await Promise.resolve()
</script>

<div {@attach () => { console.log('never runs') }}></div>

Reproduction

REPL

Severity

blocking all usage of svelte

[PatrickG]

#16627

[dummdidumm]

Closing as duplicate of #16627