Add sequence support for identity on GPU (#7810)
* Add sequence supprot for identity on GPU
* implement TensorSeq in provider interface
* fix definition err
* Add new interface to TensorSeq
* fix comments
* fix comments
* fix mac warning
* move TensorSeq forward declaration
* add TensorSeq header
* remove declaration
* fix minor format
* fix minor format
* define TensorSeq as struct
Co-authored-by: RandySheriffH <rashuai@microsoft.com>
