kill TK_NAMED_TUPLE_DEF (#24350)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/24350
`TK_NAMED_TUPLE_DEF` shouldn't exist, because NamedTuples are not
distinct syntactic things. The fact that NamedTuples and Classes are
treated differently is a property of our implementation, not the
language grammar.
This PR kills it and re-uses `CLASS_DEF` instead.
Test Plan: Imported from OSS
Differential Revision: D16825273
Pulled By: suo
fbshipit-source-id: f6d97d7e4fbdf789fd777f514eac97f32e2bbae2
