Support default values on NamedTuple fields (#54682)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/54682
Test Plan: Imported from OSS
Reviewed By: gmagogsfm
Differential Revision: D27327241
Pulled By: ansley
fbshipit-source-id: 76546f1770d50ebc3435bba3b74540e3c6be8a1c
