[FX] Native callables in FX lowering (#43426)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/43426
Test Plan: Imported from OSS
Reviewed By: zdevito
Differential Revision: D23273427
Pulled By: jamesr66a
fbshipit-source-id: 3a9d04486c72933d8afd9c181578fe98c3d825b0
