The shortcut we put in place didn't resolve percentage widths and
ignored border spacing. We can still return early after we compute the
width per the specifications.
Since there are no table-specific boxes anymore it would be nice to
output their types additionally in layout dump so we can tell table
boxes from "regular" boxes.
Solves conflict in layout tree "type system" when elements <label> (or
<button>) can't have `display: table` because Box can't be
Layout::Label (or Layout::ButtonBox) and Layout::TableBox at the same
time.
Width of table wrapper need to be set to to calculate width of table
box inside. Otherwise TFC will set wrong width assuming width of
containing block is 0.
