Update WebSocket blocked ports to match the Fetch spec
Adresses #9949.
This adds a function that tests whether a request should be blocked or not based on it's url's scheme and port. It also adds testing for port restriction to the `main_fetch` method. More info in eb07418c83.
@Ms2ger In https://github.com/whatwg/html/issues/841, @annevk proposes to remove port restrictions from websockets. Should we go ahead do that, given that the spec hasn't been changed yet?
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/10014)
<!-- Reviewable:end -->