Update checks to use `testutils.getCheckEvaluate` helper to prevent not having needed messages

There are several checks which can return a state that the check does not have a message for. This was identified in https://github.com/dequelabs/axe-core/pull/5367:

Seven checks return undefined with no incomplete message: label-content-name-mismatch, listitem, only-dlitems, only-listitems, important-letter-spacing, important-line-height, important-word-spacing.

The testutils file has a helper function getCheckEvaluate which validating that the check has a message that corresponds to the return type. We should update all our check tests to use this helper to ensure that we don't allow checks to not have messages.

- const check = checks['label-content-name-mismatch'];
+ const labelContentNameMismatchEvaluate = testutils.getCheckEvaluate('label-content-name-mismatch');

- check.evaluate(vNode.actualNode, options, vNode)
+ labelContentNameMismatchEvaluate(vNode.actualNode, options, vNode);

We'll also need to make sure that each check has a test to check for undefined (listitem uses getCheckEvaluate but does not have a test for undefined).