Fixes #16091.  Remove aria-readonly since it's only valid for role=textbox and screen readers pick it up natively from the DOM attribute for TextBox widgets.
Fixes #16091.  Remove aria-readonly since it's only valid for role=textbox and screen readers pick it up natively from the DOM attribute for TextBox widgets.

git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@29810 560b804f-0ae3-0310-86f3-f6aa0a117693

harbalk/delite,Sam-Cummins/delite,kitsonk/delite,harbalk/delite,Sam-Cummins/delite,kitsonk/delite