[StaticRuntime] Clean up (#53096)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53096
- auto[&] -> const auto[&]
- clean up size() calls
Test Plan:
```
buck test //caffe2/torch/fb/sparsenn:test
buck test //caffe2/benchmarks/static_runtime:static_runtime_cpptest
```
Reviewed By: ajyu
Differential Revision: D26747001
fbshipit-source-id: 6ec81310747d86f7c5d2d17202eef7e299ef610c
