[jit] Rewrote DFS graph iterator to remove unnecessary local state (#61326) (#61980)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/61980
Test Plan: Imported from OSS
Reviewed By: mruberry
Differential Revision: D29917766
Pulled By: laurencer
fbshipit-source-id: 536c4806636fe9e709e8bffdefa9320127064dea
