[release/11.0] [mono][aot] Fix recursive struct wrapper normalization

[github-actions]

Backport of #135438 to release/11.0.

/cc @pavelsavara

Customer Impact

• Customer reported
• Found internally

Blazor WebAssembly AOT publishing deterministically crashes
mono-aot-cross with a native stack overflow when a value type contains a
generic value-type field instantiated over the containing type. The customer
reproduction is tracked by #132071 and reproduces on .NET 10 and .NET 11.

Regression

• Yes
• No

This is an existing Mono AOT compiler limitation rather than a regression.

Testing

The corrected backport removes the invalid mutually recursive generic test
types from #135029 that caused #135348. It retains only the valid
self-recursive shape and makes the helper types private.

• .\build.cmd -bl -os browser -subset mono+libs -c Release /p:RuntimeFlavor=Mono
  • Passed with 0 warnings and 0 errors.
• Mono browser AOT on Chrome,
  System.Tests.ValueTypeTests
  • AOT-compiled 80 assemblies.
  • 23/23 tests passed.
  • XHarness exit code 0.
• Original source-only Blazor reproduction from Blazor WASM AOT Compilation Failure #132071, using the
  release/11.0 mono-aot-cross
  • App assembly compiled successfully.
  • Dedup aot-instances.dll compiled successfully (14,712/14,747 methods).
• The corrected test shape was also verified on main before [mono][aot] Fix recursive struct wrapper normalization #135438:
  • The compiler without the fix exits with 0xC00000FD.
  • The compiler with the fix successfully compiles the same test assembly.

Risk

Low. The native change is limited to recursive gsharedvt wrapper-signature
normalization. It uses the existing non-shared fallback when a value type is
encountered again or the bounded recursion depth is reached. Acyclic value
types retain their prior normalization behavior. The corrected test avoids the
invalid cross-runtime metadata that caused the original CI regression.

IMPORTANT: If this backport is for a servicing release, please verify that:

• For .NET 8 and .NET 9: The PR target branch is release/X.0-staging, not release/X.0.
• For .NET 10+: The PR target branch is release/X.0 (no -staging suffix).

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.

Note

This PR description was updated with GitHub Copilot.

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[jkotas]

The tests introduced by this PR are failing - #135348 . The fix for these failures should be included in this PR.