Implement name inference for torch.matmul (#25177)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25177
Test Plan
- new tests [namedtensor ci]
Test Plan: Imported from OSS
Differential Revision: D17051452
Pulled By: zou3519
fbshipit-source-id: 7259cdb7ba7f480035528cf3c60ef6d051e42db5
