Write tests for role="presentation"/"none" treatment for required children

[rahimabdi]

The ARIA spec states the following in Presentational Role Inheritance:

When an explicit or inherited role of none/presentation is applied to an element with the implicit semantic of a WAI-ARIA role that has Allowed Accessibility Child Roles, in addition to the element with the explicit role of none/presentation, the user agent MUST apply an inherited role of none to any accessibility descendants that do not have an explicit role defined. Also, when an explicit or inherited role of none/presentation is applied to a host language element which has specifically allowed children as defined by the host language specification, in addition to the element with the explicit role of none/presentation, the user agent MUST apply an inherited role of none to any specifically allowed children that do not have an explicit role defined.

...

For any element with an explicit or inherited role of none/presentation and which is not focusable, user agents MUST ignore role-specific WAI-ARIA states and properties for that element. For example, in HTML, a ul or ol element with a role of none/presentation will have the implicit native semantics of its li elements removed because the list role to which the ul or ol corresponds has an Allowed Accessibility Child Role of listitem. Likewise, the implicit native semantics of an HTML table element's thead/tbody/tfoot/tr/th/td descendants will also be removed, because the HTML specification indicates that these are required structural descendants of the table element.

If we haven't yet, we should write tests for this; specifically, to ensure that required children descendants of an element with presentation/role inherit properly from their parent element's role. For example, in this code snippet, the children <li> elements should also be rendered presentational:

<ul role="presentation"> <!--Should be the same for role="none"-->
    <li>item 1</li>
    <li>item 1</li>
</ul>

I believe the contextual roles WPT test should provide most of the needed test cases.

@cookiecrook I was unable to find any existing tests for this but if we don't have them, where would you suggest they reside?