[PyTorch] Use plain old function pointer for RecordFunctionCallback (#48629)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48629
Nearly every non-test callsite doesn't need to capture any variables anyway, and this saves 48 bytes per callback.
ghstack-source-id: 118568240
Test Plan: CI
Reviewed By: dhruvbird
Differential Revision: D25135415
fbshipit-source-id: 5e92dc79da6473ed15d1e381a21ed315879168f3
