Possible injection because of sanitize cache

Basically it's possible to inject dirty html:
```js
const striked = 'test';

console.log(

);
console.log();
console.log();
```

This is the output:
```html

```

Expected output:
```html

```

After rendering `

`, it caches `test` and doesn't sanitize it anymore. It can be seen live [here](https://codepen.io/remziatay/pen/YzroqLm?editors=1010) as well. Just because something was rendered before, it shouldn't mean that it's sanitized.

Start with the JavaScript reproduction in the issue and compare its three renders with the linked CodePen. Trace the sanitizer cache behavior responsible for reusing the previously rendered content; done means the third render escapes the string like the first while preserving the direct HTML render.

Vom Indexierungsmodell aus dem Issue-Text verfasst.