[VitisAI] optimize model clone (#21706)
### Description
<!-- Describe your changes. -->
Optimize the memory consumption for model_clone which is a crucial part
of our model preparation
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
This is curcial for meeting the requirement for Microsoft's 8.15
release.
---------
Co-authored-by: Yueqing Zhang <yueqingz@amd.com>
Co-authored-by: Chunye Wang <chunywan@amd.com>
