Fix type promotion of complex32 and complex32 (#27929)
Summary:
torch.promote_types(torch.complex32, torch.complex32) reports
RuntimeError.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/27929
Differential Revision: D18013017
Pulled By: nairbv
fbshipit-source-id: 14de1adb7e81694d0f1463b11f8d4c284b25502b
