Inline nodes in our layout tree have a position, so let's show it. By
centralizing the logic for this, block nodes now lose their redundant
'content-size' dump info which is already part of the box model dump.
There are some nuances to creating these wrappers, such as manually
propagating certain text styles that are not inherited by default. We
already have the logic for this in
`NodeWithStyle::create_anonymous_wrapper()`, so reuse that method in our
implementation of the button layout.
Fixes applying certain text styles (such as `text-decoration`) to the
text of a `<button>`.
We were only dumping a PaintableBox' dimensions if its layout node was a
Layout::Box as well, causing us to not dump the dimensions of paintables
for inline nodes in the paintable tree.
Browsers such as Chrome and Firefox apply an arbitrary scale to the
current font size if `normal` is used for `line-height`. Firefox uses
1.2 while Chrome uses 1.15. Let's go with the latter for now, it's
relatively easy to change if we ever want to go back on that decision.
This also requires updating the expectations for a lot of layout tests.
The upside of this is that it's a bit easier to compare our layout
results to other browsers', especially Chrome.
