Need to be able to detect javascript strict mode violations in qmllint.

If I pass a script containing the following strict mode violation to QJSEngine::evaluate, an error is detected, but nothing happens in qmllint.

'use strict';
let hello = 13;
hello2 = 14;

–

Please try the attached reproducer.
I have also included a stand-alone JS file, which you can run as follows
$qmllint error.js