Remove 2 index.html files reporting test suite status

Actually the latest files shall be
- http://www.w3.org/Style/CSS/Test/CSS3/Color/current/
- http://www.w3.org/Style/CSS/Test/MediaQueries/20120229/
which are referenced by
- http://www.w3.org/Style/CSS/Test/
Remove related index.xht and indices.css too
Merge pull request #653 from zqzhang/remove-index.html

Remove 2 index.html files reporting test suite status