[cssom-view] The spec is wrong about "the body element" disallowing frameset

[Loirooriol]

https://drafts.csswg.org/cssom-view/#dom-document-scrollingelement

Note: the body element is different from HTML’s document.body in that the latter can return a frameset element.

That's wrong: both can return a frameset element.

https://html.spec.whatwg.org/multipage/dom.html#the-body-element-2

The body element of a document is the first of the html element's children that is either a body element or a frameset element, or null if there is no such element.

The body attribute, on getting, must return the body element of the document (either a body element, a frameset element, or null).