Add ability to designate tests as "untestable"

[jugglinmike]

Preview Tests

Depends on w3c/aria-at-app#1405

[howard-e]

Having reviewed how this works in the related w3c/aria-at-app#1405 PR, I'm comfortable with the functionality and the code looks good to me.

As I mentioned in my review there, just need to call out that the requested string needs to be updated:

• Were there additional undesirable behaviors? -> Did negative side effects occur? (code)
• No, there were no additional undesirable behaviors. -> No, negative side effects did not occur. (code)
• Yes, there were additional undesirable behaviors. -> Yes, negative side effects occured. (code)
• Undesirable behaviors -> Negative side effects (this appears when the above radio option is selected, and it wasn't listed in the linked issue but seems reasonable for that copy to be used here) (code)

[jugglinmike]

Thanks for reviewing and for catching that, @howard-e! In addition to adding that critical change, I've removed the spuriously-generated files and merged in the master branch so CI won't generate them again.

[jugglinmike]

Thanks for reviewing and for catching that, @howard-e! In addition to adding that critical change, I've removed the spuriously-generated files and merged in the master branch so CI won't generate them again.

[howard-e]

Changes look good to me, thanks @jugglinmike !