Bug 1765847 [wpt PR 33735] - More consistent test for frames across a11y code, a=testonly

Automatic update from web-platform-tests
More consistent test for frames across a11y code

The difference between a frame/iframe/fencedframe and the other
types is that they should have a child document that we walk into.

Also fix clusterfuzz issue and add at least a minimal test
for <fencedframe>.

Bug: 1316969
Change-Id: I1aa3dcd4975181bdd4859f41b7e3b81db7e3b2f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3577371
Reviewed-by: Daniel Libby <dlibby@microsoft.com>
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/main@{#996383}

--

wpt-commits: 78a17b6d96c5af9030c611576848f2c15161bdce
wpt-pr: 33735

Author: Aaron Leventhal

testing/web-platform/tests/accessibility/crashtests/iframe-srcdoc.html

@@ -0,0 +1 @@
+<iframe id="frame" style="content-visibility: hidden" srcdoc="\'<table>"</table>\'></iframe>xx