[backport/9.0-staging] Disable WASI CI

[Copilot]

main PR #117936

Contributes to #128772

Description

wasm-ld from wasi-sdk is dynamically linked against libxml2.so.2, which was renamed to libxml2.so.16 in Ubuntu 26.04 (introduced via #126528). This breaks all WASI CI jobs on 9.0-staging. .NET 10 disabled WASI CI in #117936; this ports the CI-only portion of that fix to 9.0.

• eng/pipelines/runtime.yml:

  • Comment out wasi_wasm from the MonoAOTOffsets platform list
  • Remove wasi from MonoCrossAOTTargetOS and monoCrossAOTTargetOS in all three CrossAOT_Mono jobs (linux, windows, macOS)
  • Remove build_wasi_wasm_linux_release_MonoAOTOffsets from their dependsOn lists

• eng/pipelines/extra-platforms/runtime-extra-platforms-wasm.yml:

  • Comment out WASI AOT library tests (rolling + PR builds)
  • Comment out WASI smoke tests, simple-wasm-build-tests, and optional WASI library tests

Unlike #117936, the FailBuild MSBuild target is not added — only CI pipeline entries are disabled.

Customer Impact

WASI CI is currently broken on 9.0-staging, blocking rolling builds. No customer-facing runtime behavior changes.

Regression

Yes — introduced by #126528 (Ubuntu 26.04 image update).

Testing

CI-only change; no code logic modified. Validated that no active wasi/wasi_wasm references remain in the affected pipeline files.

Risk

Low. Commenting out CI jobs that are already failing. No production code or build targets touched.

Package authoring no longer needed in .NET 9

IMPORTANT: Starting with .NET 9, you no longer need to edit a NuGet package's csproj to enable building and bump the version.
Keep in mind that we still need package authoring in .NET 8 and older versions.

[dotnet-policy-service]

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