Syncing wpt PR 28316 found new untriaged test failures in CI

Tests Affected

Firefox-only failures

/html/cross-origin-embedder-policy/credentialless/cors-or-credentialless/iframe-coep-require-corp.tentative.https.html
COEP:require-corp embeds same-origin COEP:credentialless: FAIL
COEP:require-corp embeds same-origin COEP:credentialless, CORP:cross-origin: FAIL
COEP:require-corp embeds cross-origin COEP:credentialless, CORP:cross-origin: FAIL

CI Results

Gecko CI (Treeherder)
GitHub PR Head

Notes

These updates will be on mozilla-central once bug 1702218 lands.

Note: this bug is for tracking fixing the issues and is not
owned by the wpt sync bot.

This bug is linked to the relevant tests by an annotation in
https://github.com/web-platform-tests/wpt-metadata. These annotations
can be edited using the wpt interop dashboard
https://jgraham.github.io/wptdash/

If this bug is split into multiple bugs, please also update the
annotations, otherwise we are unable to track which wpt issues are
already triaged. Resolving as duplicate or closing this issue should
be cause the bot to automatically update or remove the annotation.