Missing includes prevent the creation of PCHs. So removing includes which
directly or indirectly point to missing includes is a requirement for
working PCHs.
Task-number: QTCREATORBUG-21529
Change-Id: Id55be164df590149fe1ab55c2a3a90b8b5e3bfa7
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>
