Bug 1619740 [wpt PR 22072] - Add testing for the scrolling attribute, a=testonly

Bug 1619740 [wpt PR 22072] - Add testing for the scrolling attribute, a=testonly

Automatic update from web-platform-tests
Add testing for the scrolling attribute (#22072)

The [1] CL added support for scrolling="noscroll" and
scrolling="off", but it did not add any testing of these two
values. These two values are explicitly called out in the spec [2],
so this CL adds testing.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/2083595
[2] https://html.spec.whatwg.org/multipage/rendering.html#the-page

Bug: 1057454
Change-Id: I457e22ecbe28c4b0a50ec70ba62d2c32a6c348ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2085396
Commit-Queue: Mason Freed <masonfreed@chromium.org>
Auto-Submit: Mason Freed <masonfreed@chromium.org>
Reviewed-by: Frédéric Wang <fwang@igalia.com>
Cr-Commit-Position: refs/heads/master@{#746542}

Co-authored-by: Mason Freed <masonfreed@chromium.org>
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wpt-commits: 3db076b37210231e2ac7cb6c436f5a713b448813
wpt-pr: 22072