Rebased on top of #12633. Added tests for ReduceSum. Test for square is taken care by the existing tests for Pow operator.
@anirudhacharya @Roshrini @zhreshold This PR is ready for review again. [ Full content available at: https://github.com/apache/incubator-mxnet/pull/12653 ] This message was relayed via gitbox.apache.org for [email protected]
