Enable metadata and signature changes in graph transformers (#4783)
Enable metadata and signature changes in graph transformers (#4783)

After applying all the graph transformations the metadata and signature could have changes
(e.g.: new outputs got added, or the outputs/inputs got renamed). Therefore the local
copies of metadata and signature, that InferenceSession administrated for faster lookup, has to be updated.
For this the `SaveModelMetadata`, that now has to be idempotent, should be called after resolving the transformed graph
microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime