Add reference files for Color tests t423-/424-/425-/t44- case
Merge pull request #594 from chenxix/chenxix/csswg-test/color-t-t423-4424-425-t44

Add reference file for color t423/424/424  case
Remove style-attr-cascade-README file
Merge pull request #655 from chenxix/csswg/rm-readme

Remove style-attr-cascade-README file