Add a compatibility layer in `wp-playlist.js` to avoid VM errors from MediaElement's plugin bridge in the TinyMCE views for playlists by suppressing playback for files whose mime-type is not supported in the user's browser natively.

This is similar to how audio and video shortcodes are handled: file types are whitelisted for native playback.

See #27892.



git-svn-id: https://develop.svn.wordpress.org/trunk@28171 602fd350-edb4-49c9-b593-d223f7449a82