Add APIs for custom device using TensorIteratorBase. (#120792)
1) add operand and get_dim_names API;
2) set will_resize to true when output tensor is undefined;
3) add abs_stub for dummy device and calculate on cpu device;
4) support dummy device copy with stride;
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120792
Approved by: https://github.com/ezyang
