static getPseudoRootDomain(url) {
    const hostname = Util.createOrReturnURL(url).hostname;
    const tld = Util.getPseudoTld(hostname);

    // tld is .com or .co.uk which means we means that length is 1 to big
    // .com => 2 & .co.uk => 3
    const splitTld = tld.split('.');

    // get TLD + root domain
    return hostname.split('.').slice(-splitTld.length).join('.');
  }
Returns a primary domain for provided hostname (e.g. www.example.com -> example.com).
As it doesn't consult the Public Suffix List, it can sometimes lose detail.
See the `listOfTlds` comment above for more.
This function is used only while rendering pre-10.0 LHRs. See UrlUtils.getRootDomain
for the current method that makes use of PSL.
@param {string|URL} url hostname or URL object
@return {string}