Calling scroll() on an element which is not rendered (by a parent with
display: none) would previously cause a crash. In fact, we should
terminate the algorithm
[https://drafts.csswg.org/cssom-view/#dom-element-scroll] at step 10 in
this situation.
The fix hinges on implementing Element::has_css_layout_box() correctly,
rather than just returning true in all cases as we did previously.
Fixes#19430.
