Globally disable WindowContextHelpButtonHint

Do set the global application flag AA_DisableWindowContextHelpButton
to avoid having to unset the default WindowContextHelpButtonHint
in every single dialog.

AA_DisableWindowContextHelpButton was added in Qt 5.10.

Change-Id: I21fe8bc5ddfa4c01ec7a799b04bfb6ff1c9d6d86
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/autotest/testrunner.cpp

@@ -746,7 +746,6 @@ RunConfigurationSelectionDialog::RunConfigurationSelectionDialog(const QString &
                                                                  QWidget *parent)
     : QDialog(parent)
 {
-    setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
     setWindowTitle(tr("Select Run Configuration"));
 
     QString details = tr("Could not determine which run configuration to choose for running tests");