Some of the UI elements in the a11y tests are allocated dynamically,
which means that if the test fails, the element is not destroyed
properly. As a result, the "hanging" UI elements affect all the
following tests, which leads to more test failures and even hangs.
This patch wraps all such allocations into smart pointers, which
guarantees correct destruction in case of test failure, so that other
tests are not affected, and also prevents memleaks.
As a drive-by:
- use nullptr instead of 0 in constructors;
- create some objects on stack instead of dynamically allocating
memory for them;
- remove some unneeded 'delete' calls for the objects that belong
to QObject-hierarchy.
Task-number: QTBUG-87674
Pick-to: 6.3 6.2
Change-Id: I0dcc26990955cd7b240a689a7438880b686985b7
Reviewed-by: Marc Mutz <marc.mutz@qt.io>