Automatic update from web-platform-tests layout: Ensure that `FragmentFlags` reflect current starting BoxTree layout from IFC This change ensures that when starting a `BoxTree` incremental layout from an `IndependentFormattingContext` that the `FragmentFlags` of the newly generated box reflect the current style, rather than wrongly preserving them between incremental layouts. This fixes an issue where restyling an `<li>` element with replaced content to one that was not replaced content did not remove the `IS_REPLACED` flag. Signed-off-by: Martin Robinson <martin@abandonedwig.info> Co-authored-by: Oriol Brufau <obrufau@igalia.com> -- wpt-commits: 72b780fda14c724024341740bb7ce5672d8ee794 wpt-pr: 60951