[PyTorch] Save a refcount bump in make_variable (#51180)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51180
This fast path still did a refcount bump because it copied the inner intrusive_ptr to the stack. Now it's moved.
ghstack-source-id: 120460258
Test Plan:
1) profile empty benchmark & inspect assembly to verify move
2) run framework overhead benchmarks
Reviewed By: bhosmer
Differential Revision: D26094951
fbshipit-source-id: b2e09f9ad885cb633402885ca1e61a370723f6b8
