As a developer of Qt, I'd like to be warned when I introduce new sanitizer issues

As far as I know, we have a mechanism by which new qdoc warnings are being flagged as errors on integration runs, while old warnings are allowed to remain.

A similar mechanism would be very useful to have for sanitizer errors, because if we wait for sanitizer errors to reach zero before making sanitizer-cleanness part of the integration tests, we'll wait until forever.