Refactor the throws in aria-utils

[cookiecrook]

[the throw messages in aria-utils] only a help for authors while writing the test, and a classname typo would still result in a silent failure unless all of them had the same typo, so @annevk pointed out they have limited utility.

Originally posted by @cookiecrook in https://github.com/web-platform-tests/wpt/pull/43740#discussion_r1468175855

Perhaps there is a better way to approach this.

[cookiecrook]

Actually in discussing with @rahimabdi today, any necessary changes will probably just be worked into @jugglinmike's PR for

• https://github.com/web-platform-tests/wpt/pull/42769

[zcorpan]

We discussed this in the meeting today. Please disregard @cookiecrook 's comment above, as the PR is wontfixed.