Fix autograd thread crash with python-3.9 (#50998)
Summary:
Update pybind repo to include `gil_scoped_acquire::disarm()` methods
In python_engine allocate scoped_acquire as unique_ptr and leak it if engine is finalizing for Python-3.9+
Fixes https://github.com/pytorch/pytorch/issues/50014 and https://github.com/pytorch/pytorch/issues/50893
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50998
Reviewed By: ezyang
Differential Revision: D26038314
Pulled By: malfet
fbshipit-source-id: 035411e22825e8fdcf1348fed36da0bc33e16f60
