[SR] Clean up GetLivenessMap (#66606)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66606
- Remove dead code (see comment for where)
- Add debug prints
- Small reorganization of the code to improve readability
Reviewed By: d1jang
Differential Revision: D31568219
fbshipit-source-id: 50240c325bf4fd012e1947ac931bb67c6f5dfafb
