aria-required-children gives a confusing message on presentational role conflict

The following appropriately fails the aria-required-children, because despite the child having role=presentation, tabindex=-1 causes the element not to get skipped in the accessibility tree.

The message this results in is "Element has children which are not allowed: [role=presentation]" is misleading though. role=presentation is allowed, what's causing a problem here is tabindex.

```html

**Expectatoin**: The message for this should be something like: "Element has presentational children which cannot be ignored because of [tabindex=-1]"