This removes the majority of `../../../../../../test_util` relative
imports from the codebase, allowing us to move this code more easily in
the future.
This adds support for the URLPattern API.
The API is added in --unstable only, as it has not yet shipped in any
browser. It is targeted for shipping in Chrome 95.
Spec: https://wicg.github.io/urlpattern/
Co-authored-by: crowlKats < crowlkats@toaxl.com >
