Add dotnet/diagnostics to source-build

[omajid]

This produces the Microsoft.Diagnostics.NETCore.Client package that's
shipped as part of the Microsoft SDK too.

Adding this also adds some additional dependencies:

<AnnotatedUsage Id="Microsoft.NETCore.DotNetAppHost" Version="2.1.0" File="src/diagnostics.b6de9d322756aed892dafa0aed0053caa7db4fa6/artifacts/obj/Microsoft.Diagnostics.NETCore.Client/project.assets.json" Project="src/diagnostics.b6de9d322756aed892dafa0aed0053caa7db4fa6/" SourceBuildPackageIdCreator="runtime MicrosoftNETCoreDotNetAppHostPackageVersion/5.0.0-preview.8.20407.11" />
<AnnotatedUsage Id="Microsoft.NETCore.DotNetHostPolicy" Version="2.1.0" File="src/diagnostics.b6de9d322756aed892dafa0aed0053caa7db4fa6/artifacts/obj/Microsoft.Diagnostics.NETCore.Client/project.assets.json" Project="src/diagnostics.b6de9d322756aed892dafa0aed0053caa7db4fa6/" SourceBuildPackageIdCreator="runtime MicrosoftNETCoreDotNetHostPolicyPackageVersion/5.0.0-preview.8.20407.11" />
<AnnotatedUsage Id="Microsoft.NETCore.DotNetHostResolver" Version="2.1.0" File="src/diagnostics.b6de9d322756aed892dafa0aed0053caa7db4fa6/artifacts/obj/Microsoft.Diagnostics.NETCore.Client/project.assets.json" Project="src/diagnostics.b6de9d322756aed892dafa0aed0053caa7db4fa6/" SourceBuildPackageIdCreator="runtime MicrosoftNETCoreDotNetHostResolverPackageVersion/5.0.0-preview.8.20407.11" />
<AnnotatedUsage Id="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" File="src/diagnostics.b6de9d322756aed892dafa0aed0053caa7db4fa6/artifacts/obj/Microsoft.Diagnostics.NETCore.Client/project.assets.json" IsDirectDependency="true" IsAutoReferenced="true" Project="src/diagnostics.b6de9d322756aed892dafa0aed0053caa7db4fa6/" />

But all of these Package+Version usages are already present in the file.

[dagood]

About these:

/src/repos/Directory.Build.targets(553,5): error : 6 new packages used not in baseline! See report at /src/artifacts/prebuilt-report/baseline-comparison.xml for more information. Package IDs are: [/src/repos/known-good.proj]
/src/repos/Directory.Build.targets(553,5): error : Microsoft.CodeAnalysis.FxCopAnalyzers.3.0.0-beta3.final [/src/repos/known-good.proj]
/src/repos/Directory.Build.targets(553,5): error : Microsoft.CodeAnalysis.VersionCheckAnalyzer.3.0.0-beta3.final [/src/repos/known-good.proj]
/src/repos/Directory.Build.targets(553,5): error : Microsoft.CodeQuality.Analyzers.3.0.0-beta3.final [/src/repos/known-good.proj]
/src/repos/Directory.Build.targets(553,5): error : Microsoft.DotNet.Arcade.Sdk.5.0.0-beta.20364.3 [/src/repos/known-good.proj]
/src/repos/Directory.Build.targets(553,5): error : Microsoft.NetCore.Analyzers.3.0.0-beta3.final [/src/repos/known-good.proj]
/src/repos/Directory.Build.targets(553,5): error : Microsoft.NetFramework.Analyzers.3.0.0-beta3.final [/src/repos/known-good.proj]

I'm running a branch build to get a baseline, it's possible the rc1 PR is conflicting (in a non-Git way) with other PRs I just merged that we didn't re-run full CI for. https://dev.azure.com/dnceng/public/_build/results?buildId=861529&view=results

[dagood]

/src/repos/Directory.Build.targets(553,5): error : Microsoft.DotNet.Arcade.Sdk.5.0.0-beta.20364.3 [/src/repos/known-good.proj]

This is probably from https://github.com/dotnet/diagnostics/blob/b6de9d322756aed892dafa0aed0053caa7db4fa6/global.json#L16... we have infra to replace it for arcade builds by modifying the global.json, but I think you need to point at the global.json with a prop in the .proj file to activate that. sourcelink.proj might be a reasonable minimal example of that.

A pattern to restrict the build to a specific project (when ExcludeFromSourceBuild isn't working and a project-specific build command won't reasonably work either) is to delete stuff out of the sln file to let the default build command build the subset: https://github.com/dotnet/source-build/blob/master/patches/linker/0001-Remove-test-projects-from-solution.patch

Other ones seem "real" too, other PRs and the manual build seem to be going fine. 😕

[omajid]

This doesn't seem to have removed the prebuilt... This PR was done before the update to RC1, and it looks like RC1 uses a different commit of the dotnet/diagnostics repo.

[dagood]

Looks good now after your new commit!

<BaselineComparison>
  <Removed>
...
    <PackageIdentity Id="Microsoft.Diagnostics.NETCore.Client" Version="0.2.0-preview.20419.2" />
...
    <PackageIdentity Id="runtime.placeholder-rid.Microsoft.NETCore.CoreDisTools" Version="1.0.1-prerelease-00005" />
...
  </Removed>
</BaselineComparison>