Allow for string literal return during symbolic tracing (#47618)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/47618
Test Plan: Imported from OSS
Reviewed By: jamesr66a
Differential Revision: D24870422
Pulled By: ansley
fbshipit-source-id: 41c56c2f4f1f7bb360cea0fb346f6e4d495f5c2b
