Move media (as in audio/video) tests to media/

fast/media/ contains media queries tests, with the exception of two
tests, one if which was added by me. Let them live with the other
audio/video tests and remove fast/media/ from the media watchlist.

BUG=none

Review URL: https://codereview.chromium.org/74783002

git-svn-id: svn://svn.chromium.org/blink/trunk@162216 bbb929c8-8fbe-4397-9dbb-9b2b20218538