[whatwg] [editing] New conformance tests

[Aryeh Gregor]

I've had some type of tests around for a while now, but they weren't
suitable for implementers.  I've now recoded and reformatted them so
that they output a table of results using James Graham's
testharness.js.  The link is here, but WARNING: it will run script
continuously for a few minutes, which will freeze Firefox (Chrome is
fine):

http://aryeh.name/spec/editing/conformancetest/runtest.html

I haven't tested it yet in IE or Opera, but obviously that's fairly
high on my priority list.  I also intend to break it up into more
manageable chunks so it doesn't freeze the tab or browser for quite so
long.  The tests are documented in the specification itself:

http://aryeh.name/spec/editing/editing.html#tests

There are currently 56,720 individual tests, some of which contain
several independent assertions.  Most of the tests are
queryCommand*()-related, since I generally run six such tests
(indeterm, state, value; before, after) for each command executed.  I
would greatly appreciate feedback if anyone spots tests that don't
seem to give reasonable or correct results -- that could signify a bug
in the test suite and/or the spec.

This is just a first pass, I still have a bunch of cleanup to do.
Nevertheless, feedback appreciated!