Terminating a thread that we don't have full control over might leave
mutexes or critical sections locked, ending up with an application that
can't allocate memory or open new windows.
Also, if terminating of the thread would fail (which the code tried to
handle), then deleting the QThread anyway would have triggered the
assertion that we don't delete a running thread in ~QThread.
So simplify this code: wait simply returns true if the thread isn't
running anymore, no need for the double-check. Leave the thread running
and leaking if it is stuck somewhere in Windows APIs while executing the
native dialog.
Fixes: QTBUG-103984
Change-Id: I34aa42cbde7c769a58c14bf524781cf3abd13b70
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
c450285c41