This tests that a media element ie: <Audio> or <video>, without tabindex can be selected with keyboard (TAB Key)

SUCCESS: Tab-Key did tab to the Media Element (video1). TEST: WithTabIndexVideo.
SUCCESS: Tab-Key did tab to the Media Element (video2). TEST: WithoutTabIndexVideo.
SUCCESS: Tab-Key did tab to the Media Element (video3). TEST: WithoutControlsButWithTabIndexVideo.
SUCCESS: Tab-Key did tab to the Media Element (audio1). TEST: WithoutTabIndexAudio.
SUCCESS: Tab-Key did not tab to the Media Element (audio2). TEST: WithoutControlaAndTabIndexAudio.