The test is testing whether the order of creating a child window
of a modal dialog and showing the parent dialog matters. But to
allow child windows of a modal dialog to become active that child
also needs to be a dialog. That's a limitation on macOS, where
only NSPanel subclasses can override worksWhenModal.
Fix the test, and rewrite it using more modern idioms, avoiding
the need for long waits in the test.
Pick-to: 6.6 6.5
Change-Id: Ifb640d0288a3c7ed37f2c61294e34cd96fba49ca
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
1af821825a