The testdriver.js file was updated to provide slightly better feedback when things are not implemented by test_driver_internal. We should resync!
<rdar://problem/108355773>
Pull request: https://github.com/WebKit/WebKit/pull/13011
Committed 263283@main (7684dab4ab76): <https://commits.webkit.org/263283@main> Reviewed commits have been landed. Closing PR #13011 and removing active labels.