[LT] Remove torch::lazy::convertShapes (#71291)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71291
This commit removes torch::lazy::convertShapes since it's no longer used.
In addition, it replaces a numel logic within LTCTensorImpl.
Test Plan:
./build/bin/test_lazy
CI in lazy_tensor_staging branch
Reviewed By: wconstab
Differential Revision: D33575084
Pulled By: alanwaketan
fbshipit-source-id: b104ef39fd552822e1f4069eab2cb942d48423a6
