[sparsity][refactor] Rename row/col to out/in features
Summary: Names such as `row_block_size` and `col_block_size` might be ambiguous, especially if different engines use different tensor layouts (i.e. rows=output features, etc.). Having names such as `out_features_block_size` and `in_features_block_size` makes more sense
Test Plan:
`buck test mode/opt //caffe2/torch/fb/model_optimization:sparsity_test`
```
Building with Remote Execution [RE]. Used 36:09 minutes of total time.
[RE] Waiting on 0 remote actions. Completed 264 actions remotely.
Building: finished in 02:34.4 min (100%) 18884/18884 jobs, 420 updated
Total time: 02:34.8 min
More details at https://www.internalfb.com/intern/buck/build/b34b5c52-eba6-4e17-92f9-1f5ce620f8f0
Tpx test run coordinator for Facebook. See https://fburl.com/tpx for details.
Running with tpx session id: 8fe8fa95-c1f8-4b4f-9cbf-88b3b1b28eaf
Trace available for this run at /tmp/tpx-20210302-000019.503678/trace.log
Started reporting to test run: https://www.internalfb.com/intern/testinfra/testrun/4785074650825194
✓ ListingSuccess: caffe2/torch/fb/model_optimization:sparsity_test - main (4.094)
✓ Pass: caffe2/torch/fb/model_optimization:sparsity_test - test_sparse_qlinear (caffe2.torch.fb.model_optimization.test.sparsity.quantized_test.TestQuantizedSparseKernels) (1.896)
✓ Pass: caffe2/torch/fb/model_optimization:sparsity_test - test_sparse_qlinear (caffe2.torch.fb.model_optimization.test.sparsity.quantized_test.TestQuantizedSparseLayers) (1.907)
✓ Pass: caffe2/torch/fb/model_optimization:sparsity_test - test_sparse_qlinear_serdes (caffe2.torch.fb.model_optimization.test.sparsity.quantized_test.TestQuantizedSparseLayers) (2.035)
Summary
Pass: 3
ListingSuccess: 1
Finished test run: https://www.internalfb.com/intern/testinfra/testrun/4785074650825194
```
Reviewed By: dskhudia
Differential Revision: D26747065
fbshipit-source-id: 685fe864062ed532de284b22db757a921806d4ab