Update mozilla CSS reftests as of 2017-04-20 (#5621)

The only change in this is https://bugzilla.mozilla.org/show_bug.cgi?id=1357951, which was by me, and reviewed by @SimonSapin (which was made as a result of CSS WG discussions this morning).

View on GitHub: https://github.com/w3c/web-platform-tests/pull/5621

Received on Thursday, 20 April 2017 13:16:07 UTC