bootstrap: libs.tests subsets fails

[am11]

On linux-riscv64:

$ ./build.sh --bootstrap

succeeds. Then the subsequent libs.tests build fails:

$ ./build.sh libs.tests --use-bootstrap
  Determining projects to restore...
  Tool 'coverlet.console' (version '6.0.4') was restored. Available commands: coverlet
  Tool 'dotnet-reportgenerator-globaltool' (version '5.4.3') was restored. Available commands: reportgenerator
  Tool 'microsoft.dotnet.xharness.cli' (version '10.0.0-prerelease.25255.1') was restored. Available commands: xharness
  Tool 'microsoft.visualstudio.slngen.tool' (version '11.1.0') was restored. Available commands: slngen
  
  Restore was successful.
  All projects are up-to-date for restore.
  Determining projects to restore...
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018: The "ResolveAppHosts" task failed unexpectedly. [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018: System.IO.DirectoryNotFoundException: Could not find a part of the path '/home/am11/projects/runtime/artifacts/bootstrap/ridgraph/runtime.json'. [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at Interop.ThrowExceptionForIoErrno(ErrorInfo errorInfo, String path, Boolean isDirError) [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at Microsoft.Win32.SafeHandles.SafeFileHandle.Open(String fullPath, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 preallocationSize, UnixFileMode openPermissions, Int64& fileLength, UnixFileMode& filePermissions, Boolean failForSymlink, Boolean& wasSymlink, Func`4 createOpenException) [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at System.IO.Strategies.OSFileStreamStrategy..ctor(String path, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 preallocationSize, Nullable`1 unixCreateMode) [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, Int64 preallocationSize) [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at System.IO.File.OpenRead(String path) [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at NuGet.RuntimeModel.JsonRuntimeFormat.ReadRuntimeGraph(String filePath) [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at Microsoft.NET.Build.Tasks.RuntimeGraphCache.GetRuntimeGraph(String runtimeJsonPath) [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at Microsoft.NET.Build.Tasks.ResolveAppHosts.GetHostItem(String runtimeIdentifier, List`1 knownAppHostPacksForTargetFramework, IDictionary`2 packagesToDownload, String hostNameWithoutExtension, String itemName, Boolean isExecutable, Boolean errorIfNotFound) [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at Microsoft.NET.Build.Tasks.ResolveAppHosts.ExecuteCore() [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at Microsoft.NET.Build.Tasks.TaskBase.Execute() [/home/am11/projects/runtime/Build.proj]
/home/am11/projects/runtime/.dotnet/sdk/10.0.100-preview.5.25255.3/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets(188,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(TaskExecutionHost taskExecutionHost, TaskLoggingContext taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask) [/home/am11/projects/runtime/Build.proj]
  Nothing to do. None of the projects specified contain packages to restore.

cc @jkoritzinsky

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[ericstj]

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