Revert "Allow moc to handle symbols that have been redefined."

Revert "Allow moc to handle symbols that have been redefined."

This reverts commit 5bb1408927b4eb5a03e8ab9f7cbc68f80d8a3962.

The temporary measure used to support redefinition of QtDeclarative
class names during the transition period is no longer required.

Task-number: QTBUG-24517
Change-Id: Ib90f08fcdfb02e004e594ac72b698eaa0325d98d
Reviewed-by: Kent Hansen <kent.hansen@nokia.com>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>