Sparse CSR: Add torch.empty (#63509)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63509
The primary use of `torch.empty` is to reserve memory for tensor and set the type, device, size information. The same is done here for SparseCSR.
`crow_indices` is initialized as an empty tensor of size `num_rows + 1`. `col_indices` and `values` are initialized as empty tensors of size 0.
cc nikitaved pearu cpuhrsch IvanYashchuk
Test Plan: Imported from OSS
Reviewed By: anjali411
Differential Revision: D31770359
Pulled By: cpuhrsch
fbshipit-source-id: c83f2a2e0d7514ba24780add1086e1bccf541dd9
