GetModelNodes not compatible with multi-file saved models

[JakeRadMSFT]

System information

• OS version/distro: Windows
• .NET Version (eg., dotnet --info): ML.Net 0.8.0

Issue

• What did you do?
  Tried to call GetModelNodes on a Tensor Flow model that was successfully able to be loaded using ScoreTensorFlowModel.
• What happened?
  Received Exception: Access Denied Error
• What did you expect?
  Successfully load model and enumerate model nodes.

Source code / logs

I believe it's because it's trying to load my folder path as a file:

machinelearning/src/Microsoft.ML.TensorFlow/TensorFlow/TensorflowUtils.cs

Line 83 in bdc9a9e

var bytes = File.ReadAllBytes(modelFile);

[JakeRadMSFT]

@yaeldekel

[Ivanidzo4ka]

So I think it tensor flow terminology it's called unfrozen model, and you are absolutely right, GetModelNodes was written before we start support it, and it hasn't been updated.