Make helper plug gap in JSDOM's DOM API
Make helper plug gap in JSDOM's DOM API

Errors fired from JSDOM showed it doesn't support
`window.scrollTo` (or `window.scroll` for that
matter).

This stubs it, to the extent that our use (jQuery
really) of it works.

alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin