Fix Fuzz Testing CI (#19228)

### Description
<!-- Describe your changes. -->
Add BuildArch

To verify:
https://aiinfra.visualstudio.com/Lotus/_build/results?buildId=400952&view=logs&j=5b022bb4-70a7-5401-8766-a8a7802c7150&t=291e85c7-5547-590b-50de-4e01fcd4eba3&l=14

### 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. -->

Author: yf711

tools/ci_build/github/azure-pipelines/win-ci-fuzz-testing.yml

@@ -28,7 +28,7 @@ jobs:
     parameters:
       EnvSetupScript: $(EnvSetupScript)
       DownloadCUDA: false
-      BuildArch: $(buildArch)
+      BuildArch: x64
       BuildConfig: $(BuildConfig)
       MachinePool: 'onnxruntime-Win-CPU-2022'
       WithCache: true