Cleanup up copy-family ops (#1557)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/1557

Clean up and refactor dependency/arg checks for copy-family ops:

 - expand_copy
 - select_copy
 - split_copy
 - t_copy
 - to_copy
 - unsqueeze_copy

Reviewed By: manuelcandales

Differential Revision: D52550625

fbshipit-source-id: 418ddf21cedf73701b2fbe76921f1fedb7091742