[FRONTEND] tensorflow GatherNd function error

[adobay]

in relay/frontend/tensorflow.py, GatherNd's converter function is relay's gather_nd, but gather_nd in relay follows the mxnet semantics where each column indicates the indices in the data, which is completely different to tensorflow.

[tqchen]

cc @kazum @srkreddy1238 @icemelon9 Would be great if we can look into this.

Also perhaps we should have a discussion in the discuss forum about existing API conventions for gather nd so that we have a clear picture about what they are and how can we convert from one another

[icemelon]

Yes, I've open a topic in the discussion forum. Let's discuss there.
https://discuss.tvm.ai/t/gather-nd-semantics/6243