aria-prohibited-attr should always report incomplete if there is text in the subtree

[WilcoFiers]

The following should have been reported as incomplete, but is failed instead:

<div role="code" aria-label="foo">Hello world</div>

It should only fail if the content is missing, like in the following:

<div role="code" aria-label="foo"></div>

This already works without the role. It goes bad because subtreeText isn't called correctly.

[padmavemulapati]

Validated with the latest dev branch code base, and the test snippet
<div role="code" aria-label="foo">Hello world</div> , it is showing incomplete results as shown in the screenshot:

It was failing earlier with the same code snippet instead incomplete

It fails when <div role="code" aria-label="foo"></div>