Enable broadcasting of batch dimensions RHS and LHS tensors for lu_solve (#24333)
Summary:
Changelog:
- Enable broadcasting of RHS and LHS tensors for lu_solve. This means that you can now have RHS with size `3 x 2` and LHS with size `4 x 3 x 3` for instance
- Remove deprecated behavior of having 2D tensors for RHS. Now all tensors have to have a last dimension which equals the number of right hand sides
- Modified docs
Pull Request resolved: https://github.com/pytorch/pytorch/pull/24333
Test Plan: - Add tests for new behavior in test_torch.py with a port to test_cuda.py
Differential Revision: D17165463
Pulled By: zou3519
fbshipit-source-id: cda5d5496ddb29ed0182bab250b5d90f8f454aa6
