de-DE weekday/time formats don't match native browser implementation

Example:

```js
new Intl.DateTimeFormat('de-DE', {weekday: 'short', hour: 'numeric'})
  .format(new Date('2019-08-14T05:36:24.200Z'))
```

Chrome/Firefox: `Mi, 07 Uhr`
Intl (@1.2.5): `Mi., 7`

This is particularly problematic when doing SSR, where we polyfill `Intl` on the server (to get all locales), but rely on the native browser implementation on the client.