[PyTorch] Fix missing move in torch::jit::Lexer::next (#64653)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64653
Saves shared_ptr refcount inc/dec in SourceRange.
ghstack-source-id: 137608457
Test Plan: Profiled startup of framework overheads benchmark from high_per_models; self time spent in next() is way down.
Reviewed By: dhruvbird
Differential Revision: D30739240
fbshipit-source-id: ac455678c9d46e657b111d3788d4369983028674
