[oneDNN] Fix for failures while fusing Mul-Maximum into LeakyRelu
Hi @ezhulenev Can you please review this PR ? Thank you!
For several BF16 models, it was observed that if the Mul-Maximum pattern is not fused in the first remapper pass, then the `Cast` gets converted to a `Const` before the second remapper pass, which results in a `core dumped` failure while fetching the value of alpha for LeakyRelu because it is not a `float` val: [`alpha_val = alpha_tensor.flat<float>()(0);`](https://github.com/tensorflow/tensorflow/blob/master/tensorflow/core/grappler/optimizers/remapper.cc#L1735). This PR provides a fix for that failure.