Remove _load_return_value from RPC internal.py (#34492)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/34492
Differential Revision: D20347468
Test Plan: Imported from OSS
Pulled By: mrshenli
fbshipit-source-id: 92388d0d50a08fb895bacacf94c7b5495b4ae2b6
