[pytorch-rpc] WireSerializer should check has_storage() (#34626)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34626
We need to check has_storage() before looking at it in
cloneSparseTensors(), to avoid gratuitously throwing.
Ideally, we'd add a test for this (I wrote one up but had to disable it),
but won't work until JIT Pickler supports sparse tensors.
ghstack-source-id: 100018077
Test Plan: buck test mode/dev-nosan caffe2/torch/fb/distributed/thriftRpcAgent/...
Differential Revision: D20399971
fbshipit-source-id: 5debfa8140eb1f949d37336330223962cc320abc
