[html-tests] picture: Flip pass condition on the media="," test and add a another test (#1265)

I had misunderstood how CSS grammar works.

http://dev.w3.org/csswg/mediaqueries-4/#typedef-media-query-list
http://dev.w3.org/csswg/mediaqueries-4/#typedef-media-query
http://dev.w3.org/csswg/css-values/#comb-one
http://dev.w3.org/csswg/mediaqueries-4/#error-handling

The empty string is not a valid `<media-query>` and so `media=","` is equivalent to `media="not all,not all"`

View on GitHub: https://github.com/w3c/web-platform-tests/pull/1265

Received on Tuesday, 30 September 2014 09:06:05 UTC