Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45551
The FP16 version of SparseNormalize op in Caffe2 is missing. This Diff adds FP16 support to unblock MC process of adding FP16 to Dper3.
Check https://fb.quip.com/L0T2AXGwUY3n#EReACAeifk3 .
One question is whether the pure FP16 Sparse Normalized op will affect the accuracy? Maybe we should do it in FP32 domain.
ghstack-source-id: 114184398
Test Plan:
```
buck run mode/opt //caffe2/caffe2/python/operator_test:sparse_normalize_test
```
```
buck run mode/opt -c python.package_style=inplace mode/no-gpu //caffe2/caffe2/python/benchmarks:sparse_normalize_benchmark -- --fp16
```
Reviewed By: jspark1105
Differential Revision: D24005618
fbshipit-source-id: 8b918ec4063fdaafa444779b95206ba2b7b38537
