[PyTorch] Remove unnecessary shared_ptr copies in ThreadLocalDebugInfo::get (#47791)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47791
`debug_info` is `thread_local` and this function is a leaf, so nobody else could free it out from under us. Regular pointer should be fine.
ghstack-source-id: 116456975
Test Plan: Run framework overhead benchmarks
Reviewed By: bhosmer
Differential Revision: D24901749
fbshipit-source-id: c01a60b609fd08e5200264d8e98d356e2c78cf28
