Request's origin needs to be set for [[Update]] algorithm

[makotoshimazu]

Currently [[Soft Update]] set null as the client, and [[Update]] uses null client as a fetch client settings object on "Fetch a classic (or module) worker script" without setting origin of the request.
That will results in null as the request's origin, but it would contradicts with the request's mode (same-origin).
We would need to set the origin explicitly in the update algorithm.