The budget cuts outlined by Governor Tom Corbett could have more than twice the impact on the North Penn School District than originally thought.   Officials there now put the damage at more than four million dollars.   Figures released by Harrisburg indicate that among all the school districts in Pennsylvania, North Penn has the most to loose from planned reductions in the state reimbursement of employee social security taxes.   District officials say the cuts will make it even more difficult to put together their own budget for the next school year.