After r264272, the test does not show the bottom row, with the `color(srgb R G B / 0.6)` background-color property. History: https://results.webkit.org/?suite=layout-tests&test=css3%2Fcolor%2Fcomposited-solid-backgrounds.html
Created attachment 404331 [details] Patch
Committed r264448: <https://trac.webkit.org/changeset/264448>