Convert media-source*, no-autoplay* and remove-from* tests to testharness.js

Cleaning up media-source*, no-autoplay* and remove-from* 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/2065433002
Cr-Commit-Position: refs/heads/master@{#399407}
6 files changed