Handle additional live allocations not in checkpointed state (#94943)
We choose to ignore certain blocks that are currently allocated when we set the pool to its checkpoint. For those blocks, we need to swap out the deleter function of their corresponding blocks so that a deallocation is not triggered when they die.
Differential Revision: [D43999886](https://our.internmc.facebook.com/intern/diff/D43999886)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94943
Approved by: https://github.com/zdevito
