Add serialization logic for complex numbers (#50885)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/50885
Test Plan: Imported from OSS
Reviewed By: SplitInfinity
Differential Revision: D26094906
Pulled By: anjali411
fbshipit-source-id: 7b2614f3ee4a30c4b4cf04aaa3432988b38a0721
