Convert video-muted* and video-no* tests to testharness.js.

Cleaning up video-muted* and video-no* tests in
media/ to use testharness.js instead of video-test.js.
This will enable to upstream these tests to web-platform-tests.

BUG=588956

Review-Url: https://codereview.chromium.org/2088143003
Cr-Commit-Position: refs/heads/master@{#401258}
6 files changed