LibWeb: Support <svg> elements with display: block

There are a couple of things that went into this:

- We now calculate the intrinsic width/height and aspect ratio of <svg>
  elements based on the spec algorithm instead of our previous ad-hoc
  guesswork solution.

- Replaced elements with automatic size and intrinsic aspect ratio but
  no intrinsic dimensions are now sized with the stretch-fit width
  formula.

- We take care to assign both used width and used height to <svg>
  elements before running their SVG formatting contexts. This ensures
  that the inside SVG content is laid out with knowledge of its
  viewport geometry.

- We avoid infinite recursion in tentative_height_for_replaced_element()
  by using the already-calculated used width instead of calling the
  function that calculates the used width (since that may call us right
  back again).

Userland/Libraries/LibWeb/Layout/InlineFormattingContext.cpp

@@ -113,11 +113,11 @@ void InlineFormattingContext::dimension_box_on_line(Box const& box, LayoutMode l
     if (is<ReplacedBox>(box)) {
         auto& replaced = verify_cast<ReplacedBox>(box);
 
-        if (is<SVGSVGBox>(box))
-            (void)layout_inside(replaced, layout_mode, box_state.available_inner_space_or_constraints_from(*m_available_space));
-
         box_state.set_content_width(compute_width_for_replaced_element(m_state, replaced, *m_available_space));
         box_state.set_content_height(compute_height_for_replaced_element(m_state, replaced, *m_available_space));
+
+        if (is<SVGSVGBox>(box))
+            (void)layout_inside(replaced, layout_mode, box_state.available_inner_space_or_constraints_from(*m_available_space));
         return;
     }