Intent to unship: ::-moz-focus-outer pseudo-element.

Hi, In bug 1655859, I intend to disable parsing for ::-moz-focus-outer on all channels. This pseudo-element used to be an specific pseudo-element to show some focus outlines, but it does literally nothing anymore (other than being parsed), after the changes in bug 1636998. As part of

Searchfox now gives info about tests at the top of test files!

Have you ever been looking at a test file in Searchfox and wondered how the test could possibly work?  Then you do some more investigation and it turns out that the test, in fact, does not work and is disabled?  Perhaps you even melodramatically threw your hands up in the air in frustration?