ladybird-js support

Mostly blocked on lifecycle: `enterContext` asserts on engine started,
because Promise resolution queue is broken on ladybird-js:
```js
function f() {
  Promise.resolve().then(() => print('then'))
  print('now')
}

for (let i = 0; i < 10; i++) f()
```

Upstream bug: https://github.com/LadybirdBrowser/ladybird/issues/7757

Broken promises is a hard blocker