Auto merge of #15358 - asajeffrey:script-browsingcontext-xorigin-window, r=jdm

Allow browsing contexts to resolve to cross-origin windows

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This PR implements cross-thread `WindowProxy` objects.

At the moment, if a `Window` performs a non-similar-origin navigation, the old script thread does not update its `WindowProxy`, since the new `Window` is in the new script thread. With this PR, the `WindowProxy` is updated to a dummy `XOriginWindow` object, that only implements the whitelisted methods that are allowed to be called cross-origin.

This PR does not include working implementations of some of the cross-origin `Window` or `Location` methods.

This PR causes some cross-origin wpt tests to now pass, in particular `/html/browsers/origin/cross-origin-objects/cross-origin-objects.html ` now passes `Only whitelisted properties are accessible cross-origin`. There are some CORS failures in `fetch`, I suspect caused by the incorrect setting of `origin` in fetch requests.

Although there are some functions that now throw `SecurityException`, it is not meant to be a complete implementation, which will have to wait for XOWs to land.

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #15180.
- [X] There are tests for these changes

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