Bug 1325878 implemented a bunch more of the media query stuff, and revealed a few @import tests that were passing accidentally because of the wrong @media we used for imported stylesheets. I believe most of these failures will be gone with proper stylesheet cloning, just like the remaining test_media_queries.html failures, but worth investigating a bit more I guess. I'm tagging them with this bug number so it's easy to track them. I plan to look at this and the rest of the media query stuff tomorrow.
These are all fixed now with bug 1372041.