* upstream/master: (92 commits)
  more formatting (pytorch#8701)
  Fix pytorch#8692 (pytorch#8699)
  Create captured inputs recursively for loop to resolve loop-carried dependencies across nested blocks (pytorch#8345)
  Shard test_nn to reduce runtime for each test target (pytorch#8678)
  Create at::tensor (pytorch#8475)
  Clarify mp note about sharing a tensor's grad field. (pytorch#8688)
  Add owner rule for cpp_extension.py (pytorch#8700)
  fix formatting in :math: in fold docstring (pytorch#8696)
  Some 0-sized dimension support, port catArray away from resizeLegacy. (pytorch#8666)
  Implement flatten function (pytorch#8578)
  Created Tensor::to functions (pytorch#8643)
  Add a warning in gradcheck if inputs precision < float64 (pytorch#8663)
  Fix parsing of floating point defaults in python_arg_parser (pytorch#8681)
  Export ProcessGroupGloo options to Python (pytorch#8664)
  Fix build error in pybind_state_ideep (pytorch#8684)
  Compatibility: write nDimension/_nDimension corresponding to dim()/_dim(). (pytorch#8676)
  Improve win-build.sh for local build (pytorch#8674)
  don't do unnecessary copies for bernoulli_ (pytorch#8682)
  Use parallel if get_num_threads 0 (pytorch#8677)
  Fix serialization for Parameters (pytorch#8633)
  ...

This surfaces the options struct that can be passed to the
ProcessGroupGloo constructor to Python. By default, if no options struct
is passed at construction time, the Python bindings default to using a
struct with a TCP backed Gloo device that uses the machine's hostname to
resolve the IP address to bind to.