Rename away uses of THAllocator and THCDeviceAllocator (#16061)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16061
I discovered I needed to delete these names in preparation of moving
THCCachingAllocator to c10_cuda; might as well also fix all the other
sites too.
Reviewed By: dzhulgakov
Differential Revision: D13686869
fbshipit-source-id: e8cc55d39ac4bfd3e3a22c761f89a7a111ce5f5e
