QMetaMethod::invoke: Use normalizedType() to normalize return type

QMetaMethod::invoke: Use normalizedType() to normalize return type

The code was probably written before QMetaObject::normalizedType()
was introduced.

The behavior is covered by the existing tests
tst_QMetaObject::invokeMetaMember and
tst_QMetaObject::invokeBlockingQueuedMetaMember.

Change-Id: Ib1c3b3e4dff37947defd1dfdcc860df44539aa3a
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@nokia.com>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>