- Split layout from the styles of the row
 - Move command `.append-` `.prepend-` styles to bottom of source order
    - Actually applies styles over others in more situations which is
      probably what is expected when you add it to an element
    - Also allows us to get rid of some styles that were trying to get
      around this fact

See https://i.imgur.com/IE50PK6.png
Which is used in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/15064

Design from https://gitlab.com/gitlab-org/gitlab-ce/issues/38464

This stops the checkElementsInView method from running when there aren't any lazy load images on the page. By calling this method we are causing an unnecessary reflow which on large pages is a massive performance issue

This reverts merge request !15009

increased perf of scrolling tabs into view

spec fixes

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/39188