This is one big reason for the event refactoring: even though Flickable doesn't explicitly deal with touch events, it should be able to replay them to delegates that do care about receiving actual touches instead of fake mousepresses. (Further, Flickable should be able to flick via touch, because its event handling code can probably become agnostic about the device the event comes from: touch and mouse events begin to look more alike. But we'll see about that.)
After https://codereview.qt-project.org/c/qt/qtdeclarative/+/305381 the old hacks are somehow broken again, and it's not worth my time to fix the old hacks again when we want to do it this way instead.
As tests get disabled along the way (such as tst_TouchMouse::buttonOnDelayedPressFlickable(release before press delay is over) ) they should be listed here, and then this bug can be marked fixed when the tests are passing again.