The zoning ordinance, originally adopted August 9, 1983, by Newtown Borough, Newtown Township, Upper Makefield Township and Wrightstown Township, as subsequently amended, and entitled, Newtown Area Joint Municipal Zoning Ordinance of 1983, as amended, and all supplements and amendments thereto are hereby repealed. Provided, however, if this Newtown Area Joint Municipal Zoning Ordinance of 2006 is held to be in effective or invalid by reason of some irregularity in or impediment to its passage, this repealer shall also be ineffective as aforesaid. Then and in that event, the Newtown Area Joint Municipal Zoning Ordinance of 1983, as amended, together with its supplements and amendments, would necessarily remain in full force and effect.