[BE] Fix pybind deprecation warnings (#72376)
Summary:
Fixes:
```
../torch/csrc/autograd/python_variable.cpp:1798:33: warning: ‘bool pybind11::handle::operator==(const pybind11::handle&) const’ is deprecated: Use obj1.is(obj2) instead [-Wdeprecated-declarations]
TORCH_CHECK(out == py::none(), "Expected __torch_dispatch__ for ", op.operator_name(),
```
and
```
../torch/csrc/jit/python/python_list.cpp:254:57: warning: ‘pybind11::object::object(pybind11::handle, bool)’ is deprecated: Use reinterpret_borrow<object>() or reinterpret_steal<object>() [-Wdeprecated-declarations]
py::object(obj, /*is_borrowed*/ true),
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/72376
Reviewed By: albanD
Differential Revision: D34021328
Pulled By: malfet
fbshipit-source-id: 72906077db9031311c6b0ae4c65eb79df9c514d4
(cherry picked from commit e1877ca268b2a48d27adee9cb13f1616fb2ec487)
