Delete URLUtilsReadOnly, move members to WorkerLocation (mdn#10347)

* Delete URLUtilsReadOnly, move members to WorkerLocation

whatwg/html@32a7a20 completely removed the
URLUtilsReadOnly interface and moved/inlined/hoisted its members up
into the WorkerLocation interface. So this change deletes
URLUtilsReadOnly, and moves its members to WorkerLocation.

This change also adds spec URLs to the WorkerLocation data.

Related MDN change: mdn/content#4772

* Apply suggestions from code review

Co-authored-by: Florian Scholz <fs@florianscholz.com>

Co-authored-by: Florian Scholz <fs@florianscholz.com>

Author: sideshowbarker