LibWeb: Paint inline-level and replaced elements on top of floats

This matches CSS 2.1 appendix E, and fixes an instance of red face
border on ACID2. :^)

Userland/Libraries/LibWeb/Painting/StackingContext.h

@@ -21,6 +21,7 @@ public:
     enum class StackingContextPaintPhase {
         BackgroundAndBorders,
         Floats,
+        BackgroundAndBordersForInlineLevelAndReplaced,
         Foreground,
         FocusAndOverlay,
     };