Problem/Motivation
Once #3421202: Enable W3C-compliant webdriver testing lands we will be able to deprecate non-W3C testing and drop support for it an major version of Drupal. We will also need to ensure that #3462681: Add W3C compliant JS testing is complete.
Proposed resolution
Deprecate non-W3C testing
Remaining tasks
User interface changes
None
API changes
TBD
Data model changes
None
Release notes snippet
To do