Sync web-platform-tests PR 34741 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/34741
Details from upstream follow.

Mason Freed <masonf@chromium.org> wrote:

Remove ErrorEventInit's error's null default value

Per the spec change [1], this removes ErrorEventInit's default value
of null, which makes the error attribute have no null default.

This change has already shipped on WebKit and Gecko, and the change
makes Chromium match the spec and other implementations. This is tested
by this WPT:

wpt/html/webappapis/scripting/events/event-handler-processing-algorithm-error/document-synthetic-errorevent.html

[1] https://github.com/whatwg/html/pull/7983

Fixed: 1332448
Change-Id: Ia64a62e8c5739ab278016a94b0c3b0419d6a68f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3749784
Reviewed-by: Joey Arhar \<jarhar@chromium.org>
Commit-Queue: Joey Arhar \<jarhar@chromium.org>
Auto-Submit: Mason Freed \<masonf@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1021841}

CI Results

Ran 9 Firefox configurations based on mozilla-central, and Firefox, and Chrome on GitHub CI

Total 1 tests and 5 subtests

Status Summary

Firefox

OK : 1
PASS: 5

Chrome

OK : 1
PASS: 2
FAIL: 3

Links

Gecko CI (Treeherder)
GitHub PR Head
GitHub PR Base

https://hg.mozilla.org/mozilla-central/rev/4b2f859df754