Worker: Set AddressSpace after off-the-main-thread classic worker script fetch

This CL sets WorkerGlobalScope to AddressSpace calculated from worker script's
response URL after off-the-main-thread worker script fetch. Before this CL,
WorkerGlobalScope always uses the default AddressSpace, and it causes test
failures. This change delays calling SetAddressSpace(), but it does not change
behavior because AddressSpace should not be accessed before worker script fetch
is done.

In addition, this CL stops dedicated workers inherit their parent's AddressSpace
and instead calculates it from the worker script's response URL like shared
workers and service workers. This is aligned with the spec of AddressSpace:
https://wicg.github.io/cors-rfc1918/#integration-html
This modification does not change the behavior in basic cases because typically
dedicated workers have the same origin with its parent's origin, so there are
no changes in existing tests. Data URL workers, extension workers etc may be
affected, but we don't care them at this point because AddressSpace is still an
experimental feature and test coverage is not sufficient yet.

Change-Id: Ib8730b9950c93b95e9902b663ae7a365cb3a3b0f
Bug: 378566, 945215, 955213
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1574871
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Hiroshige Hayashizaki <hiroshige@chromium.org>
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653964}
16 files changed