This solves the long-standing problem of not being able to easily
fail a test when a certain warning is output.
[ChangeLog][QtTest] Added QTest::failOnWarning. When called in a test
function, any warning that matches the given pattern will cause a test
failure. The test will continue execution when a failure is added.
All patterns are cleared at the end of each test function.
Fixes: QTBUG-70029
Change-Id: I5763f8d4acf1cee8178be43a503619fbfb0f4f36
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
efb283fb7f