SharedWorker referrer policy should default to its context referrer policy if none is provided in its script http response

[youennf]

d1c532b

SharedWorker referrer policy should default to its context referrer policy if none is provided in its script http response
https://bugs.webkit.org/show_bug.cgi?id=260858
rdar://114625126

Reviewed by Chris Dumez.

As per https://github.com/w3c/webappsec-referrer-policy, we should default to the context initiating the first load as of referrer policy.
Implement this for SharedWorker in SharedWorkerScriptLoader.

* LayoutTests/imported/w3c/web-platform-tests/workers/modules/shared-worker-import-referrer-expected.txt:
* Source/WebCore/workers/shared/SharedWorkerScriptLoader.cpp:
(WebCore::SharedWorkerScriptLoader::notifyFinished):

Canonical link: https://commits.webkit.org/267405@main

c50873f

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	❌ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash c50873f)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	❌ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[cdumez]

LGTM

[webkit-commit-queue]

Committed 267405@main (d1c532b): https://commits.webkit.org/267405@main

Reviewed commits have been landed. Closing PR #17183 and removing active labels.