Remove failing tests from the 4.0 branch

[johnbillion]

In WordPress 4.0 and earlier, the test suite contains intentionally failing tests which are skipped when the corresponding ticket is still open. This means that once the ticket is closed as fixed it immediately causes all earlier branches to fail unless the fix is backported. Hence why the 4.0 branch and earlier have a bunch of failing tests.

A lot of time has been spent backporting fixes in both tests and src to older branches in order to get the builds to pass (#40534, #30284 and others), but this is now at the point where it's no longer practical or a good use of time.

The failing tests in the 4.0, 3.9, 3.8, and 3.7 branches should be deleted so the branch builds pass again, making them useful for the management of point releases.

[johnbillion]

In 41306:

Build/Test tools: Remove failing tests from the 4.0 branch.

See #41706

[johnbillion]

Fixed in [41306] for 4.0. I'll create separate tickets for the other branches.