Misc transformer fixes - 2 (#14156)
### Description
1. The graph pattern search introduced in
https://github.com/microsoft/onnxruntime/pull/13914/ needs to be
enhanced so that SkipLayerNormalization is supported
2. Fix fp32 parity for GPT-2 while using `SkipLayerNormalization`
fusion. The optional output of SLN needs to also include the bias (if
present) and the added output should be a sum of `input + skip + (bias)`
### Motivation and Context
Fix some breaking tests
