Update test_multi_tensor_optimizers test (#45510)
Summary:
Following up on previous [feedback](https://github.com/pytorch/pytorch/pull/45475/files#r496330797).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45510
Reviewed By: heitorschueroff
Differential Revision: D23992304
Pulled By: izdeby
fbshipit-source-id: 4784ed8d79e09da3aa61880add6443e3a8d322e4
