This was lost when QtCore, QtGui and QtWidgets were split up. Restored
now via a virtual function on QObjectPrivate.
Chose to return std::string instead of QString or QByteArray because
its SSO is usually sufficient to hold these flag strings.
[ChangeLog][QtCore][QObject] Restored printing of Qt3-style
information from dumpObjectTree().
[ChangeLog][QtWidgets][QWidget] Restored printing of Qt3-style
information from QWidget::dumpObjectTree().
Fixes: QTBUG-101732
Change-Id: I39ff5728ea5f5abbdbf81b5d7e13b8d16b6ee8b7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
f97daab7a6