Instead of rejecting invalid media-feature values at parse time, we are
expected to parse them, and then treat them as Unknown when evaluating
their media query. To implement this, we first try to parse a valid
value as before. If that fails, or we have any trailing tokens that
could be part of a value, we then scoop up all the possible
ComponentValues and treat that as an "unknown"-type MediaFeatureValue.
This gets us 66 WPT passes.
