Fix issues related to the tabbable widget

[shunguoy]

A violation "The tabbable element's role 'none' is not a widget role" is reported in the following link element in w3 home:

<a class="_iec--jumplinks__ul__a_1luhv_27 _iec--jumplinks__ul__a--selected_1luhv_74" tabindex="0">AskIBM</a>

Another example is from Yahoo Finance, a violation "The tabbable element's role 'none' is not a widget role".

<div
    tabindex="0"
    class="_yb_1of2ruh _yb_6p72fy  _yb_1q79mgk  _yb_1o0t4j7 _yb_wfiwn2"
    id="ybarAccountProfile">

In either case, the role for the element or

shouldn't be "none". Those appear as either a false positive or the role calculation is incorrect.