test on dirname attribute
submit to iframe to avoid redirect
Tests for the named access on the window object
Test when the muted IDL attribute is updated from the content attribute

Blink/WebKit has a bug here and fails the last two parser tests.
Test setting video.muted

video_muted_check.html is made redundant.
Test cloneNode- and innerHTML-created <video muted>

Presto fails the cloneNode test but nothing else.
Test more cases of setting video.muted
Test setting audio.muted

audio_muted_check.html is made redundant.
use W3C editor's draft
test on form's autocomplete attribute
tests on button element
fix test for invalid value
Test muted for document.write-created elements
use iframe load event instead of timeout
remove useless attributes
simplify test()
more use cases
Added -manual suffix to some manual dnd tests.
Renamed some renamed files.
Reorganize dnd X-doc test to fit with conventions.
Updated according to the review comments

1. Add a test to check  window['']
2. Remove two invalid assertions
3. Update some descriptions and etc.