A couple of navigation API tests rely on the `unload` event which is being deprecated

[noamr]

Test List

https://wpt.fyi/results/navigation-api/ordering-and-transition/back-cross-document-event-order.html
https://wpt.fyi/results/navigation-api/ordering-and-transition/navigate-cross-document-event-order.html

Rationale

Since unload event is being deprecated in chromium, we don't want to make these tests pass as is in chromium.
We can either:

• remove those tests from interop
• duplicate these tests, creating another version that uses pagehide instead of unload, and use the new tests in interop instead of these two.
• Keep chromium as failing these tests (we prefer not to)