onnxruntime

Fix issues for Whisper export with beam search (#15619)

### Description
This PR fixes an issue with calling the ORT transformer optimizer script
on the custom export of Whisper with beam search. It also includes the
[fix](https://github.com/microsoft/onnxruntime/pull/15616) for the GPU
out-of-memory issue.



### Motivation and Context
With this PR fix, the optimizer runs as described in the [Whisper model
optimization PR](https://github.com/microsoft/onnxruntime/pull/15473).