Add `complex64` dtype for OpInfo Reference testing (#61627)
Summary:
This PR adds `complex64` dtype testing, following conversation from: pytorch/xla#3019 ([comment](https://github.com/pytorch/xla/pull/3019#discussion_r666754943)). Original PR that added OpInfo reference testing: https://github.com/pytorch/pytorch/pull/59369.
cc: mruberry kshitij12345
Pull Request resolved: https://github.com/pytorch/pytorch/pull/61627
Reviewed By: gchanan
Differential Revision: D29710560
Pulled By: mruberry
fbshipit-source-id: 55b2e5ff47f031069335a0c75a45d4f4885ef9ac
