[VITISAI] 1. Fix reading .dat and .onnx on Linux 2. Fix issue of compiling graph twice (#17108)
### Description
<!-- Describe your changes. -->
1. Fix reading .dat and .onnx on Linux 2. Fix issue of compiling graph
twice
### 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. -->
1. Previous we have not tested large model on Linux. When the model is
sperate into .dat and .onnx, it failed to load the model.
2. Check if the provider pointer is already existed. If existed, do not
create again.