[Discuss] If `aria-labels` are supplied, add them to the `title` attribute as well?

There's a lot of duplication on the consumer side to supply both a `title` and `aria-label` especially on EuiButtonIcon.

<img width="973" alt="Screen Shot 2019-06-10 at 17 18 19 PM" src="https://user-images.githubusercontent.com/549577/59227617-c6a2d100-8ba3-11e9-83b1-7491b6c55249.png">

Is there any way we can help out the consumer but auto-providing one or the other?