Remove data_ops.h (#68312)
* Replace GetCompleteShapes() with at::infer_sizes
- Depends on landing lazy::Shape::numel()
- Also delete unused ComputeSplitCount
* Refactor ops::Squeeze to handle BuildSqueezedDimension
* Refactor Unsqueeze, delete data_ops.h/.cpp
* Fix Shape::numel, handle sizes=[], numel=1 case, mirror aten's numel()
