Migrate cpu kernel for index and index_put to c10::complex (#37877)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/37877
Test Plan: Imported from OSS
Differential Revision: D21426613
Pulled By: anjali411
fbshipit-source-id: 1bbdc0b0fc38df8a135c4cc29440b767b675324c
