[SR] Eliminate op_name_ in ProcessedNode (#71986)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71986
To address concerns over space increase from control flow.
`op_name_` was only stored as a minor optimization to avoid name lookup during logging, we can safely get rid of it. Thanks to the sampling mechanism, `get_op_name()` is called very infrequently, so this shouldn't cause too much of a regression
ghstack-source-id: 148086244
Test Plan: CI
Reviewed By: d1jang
Differential Revision: D33821005
fbshipit-source-id: 6f74eb30a54a046ca90768aebbcde22e8c435f35
(cherry picked from commit 361ba32e97dbd130938bae10b5159730822c518c)
