Make split_embedding_weights_with_scale_bias(2) scriptable

[IvanKobzarev]

Summary: Some infra like xlweights is using split_embedding_weights_with_scale_bias for torch scripted modules, mode==2 fails in torch script due to .view(torch.float16)

RuntimeError: The following operation failed in the TorchScript interpreter.
Traceback of TorchScript (most recent call last):
  File "/mnt/xarfuse/uid-128598/ebee08ee-seed-nspid4026531836_cgpid9192421-ns-4026531840/fbgemm_gpu/split_table_batched_embeddings_ops_inference.py", line 1202, in split_embedding_weights_with_scale_bias
                            (
                                weights_shifts[:, self.scale_bias_size_in_bytes :],
                                weights_shifts[:, : self.scale_bias_size_in_bytes // 2].view(torch.float16),
                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ <--- HERE
                                weights_shifts[
                                    :,

Differential Revision: D48879020

Privacy Context Container: L1138451

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This pull request was exported from Phabricator. Differential Revision: D48879020

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D48879020