Use new Streams algorithms (#1533)
* Use new Streams algorithms
Follows https://github.com/whatwg/streams/pull/1073.
* Namespacing tweaks
* No subsubsteps
Co-authored-by: Jake Archibald <jaffathecake@gmail.com>
* Missing ::
Co-authored-by: Jake Archibald <jaffathecake@gmail.com>
