Add `window.clientInformation` (alias of `navigator`)

**Describe the bug:**
`clientInformation` was Internet Explorer's renaming of `navigator`. It is specced here https://html.spec.whatwg.org/#the-navigator-object

**To Reproduce:**
Test case:
```
<script>document.title=clientInformation.userAgent</script>
```

**Platform:**
Windows 10.
