fix: hmr reload should work with async component

[kermanx]

• Tests included. Discard the changes in packages/runtime-core/src/hmr.ts, and then you will see the new test fail.
• Minimal reproduction: https://stackblitz.com/edit/vitejs-vite-qafqmi?file=src%2FComp.vue
• I think this bug was introduced by #6936
• I am 90% sure that my fix doesn't break what #6936 has fixed (I've also enhanced the existing test to prevent possible regression)
• If my fix is wrong, please point it out or only merge the tests

It's now blocking https://github.com/slidevjs/slidev/pull/1708