layout: Move text decoration propagation to stacking context tree construction (#37069)

Text decorations have a special kind of propagation. Instead of
propating these during box tree construction, move propagation to
stacking context tree construction. This will allow for using a very
easy type of incremental layout when text decorations change. For
instance, when a link changes color during hovering over it, we can skip
all of box and fragment tree construction.

In addition, propagation works a bit better now and color and style
properly move down from their originating `Fragment`s.

This introduces three new failures, because now we are drawing the
text-decoration with the correct color in more places, which exposes an
issue we have with text-decorations not being drawn in relation to the
baseline (taking into account `vertical-align`).

Testing: There are tests for these changes.
Fixes #31736.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>

components/layout/flow/float.rs

@@ -897,8 +897,7 @@ impl FloatBox {
                 info,
                 display_inside,
                 contents,
-                // Text decorations are not propagated to any out-of-flow descendants
-                propagated_data.without_text_decorations(),
+                propagated_data,
             ),
         }
     }