Add MLFloat16 support for LayerNormalization, SkipLayerNormalization (#22063)
Add `MLFloat16` support for:
- `LayerNormalization`
- `SimplifiedLayerNormalization`
- `SkipLayerNormalization`
- `SkipSimplifiedLayerNormalization`
There are existing `LayerNormTest` unit tests that cover the `MLFloat16`
functionality for `LayerNormalization` once `MLFloat16` is registered
(for example
[`LayerNormTest.LayerNorm_Scale_Float16Input`](https://github.com/microsoft/onnxruntime/blob/91c916f9c6263d1c437ec7eda222d7f6b8817175/onnxruntime/test/contrib_ops/layer_norm_op_test.cc#L112)).
Similarly, there are unit tests such as
[`SkipLayerNormTest.SkipLayerNormBatch1_Float16`](https://github.com/microsoft/onnxruntime/blob/91c916f9c6263d1c437ec7eda222d7f6b8817175/onnxruntime/test/contrib_ops/skiplayernorm_op_test.cc#L255)
that cover MLFloat16 inputs for `SkipLayerNormalization`.