[AIX]Blocking the call of dladdr under _AIX (#26513)
### Description
In AIX, dladdr() is not supported so blocking the call of dladdr API
under _AIX.
we don't have support of cpuinfo pkg also which generates a warning at
runtime.
This PR is to fox the issues mentioned above.
### Motivation and Context
1. Fix for below compilation error
```
/home/buildusr/jenkins/workspace/onnxruntime-openxl/onnxruntime/onnxruntime/core/platform/posix/env.cc:562:9: error: unknown type name 'Dl_info'
562 | if (Dl_info dl_info{};
```
2. Fix for below warning during test application executions.
`2025-11-06 07:23:44.176700000 [W:onnxruntime:Default, cpuid_info.cc:95
LogEarlyWarning] Unknown CPU vendor. cpuinfo_vendor value: 0`
