Adblocker bypass when appending dots at the end of URLs

Both `static.ads-twitter.com` and `static.ads-twitter.com.` resolve to the same IP address, but only one of them is blocked (in aggressive mode) by our adblocker. The browser treats these as different origins, but in DNS they are the same. It's not clear exactly what we should do about this, but at the very least, we should make sure that we are able to add trailing dots to adblock rules if sites end up using this as an evasion tactic. Originally reported on https://hackerone.com/reports/3643431