Incremental builds are broken in Roslyn.sln.

[CyrusNajmabadi]

Using:

Repro steps.

1. Build Roslyn.sln.
2. Build Roslyn.sln again

First time succeeds with:

WARNING: Potential build performance issue in 'IntegrationTestBuildProject.csproj'. The project does not appear up-to-date after a successful build: Output 'D:\github\roslyn\artifacts\bin\IntegrationTestBuildProject\Debug\net45\IntegrationTestBuildProject.dll' does not exist, not up-to-date. See https://aka.ms/incremental-build-failure.
========== Rebuild All: 207 succeeded, 0 failed, 0 skipped ==========
========== Rebuild completed at 2:10 PM and took 03:20.100 minutes ==========

Second time causes roslyn to rebuild 30 projects, even though nothing has changed:

...
30>PrepareTests -> D:\github\roslyn\artifacts\bin\PrepareTests\Debug\net8.0\PrepareTests.dll
30>RunTests -> D:\github\roslyn\artifacts\bin\RunTests\Debug\net8.0\RunTests.dll
30>VisualStudio.SetupPackage -> D:\github\roslyn\artifacts\obj\Microsoft.CodeAnalysis.Compilers.Setup.x64\Debug\net472\Microsoft.CodeAnalysis.Compilers.x64.vsix
30>VisualStudio.SetupPackage -> D:\github\roslyn\artifacts\obj\Microsoft.CodeAnalysis.Compilers.Setup.x86\Debug\net472\Microsoft.CodeAnalysis.Compilers.x86.vsix
30>Microsoft.CodeAnalysis.Workspaces.MSBuild.UnitTests -> D:\github\roslyn\artifacts\bin\Microsoft.CodeAnalysis.Workspaces.MSBuild.UnitTests\Debug\net8.0\Microsoft.CodeAnalysis.Workspaces.MSBuild.UnitTests.dll
30>VisualStudio.SetupPackage -> D:\github\roslyn\artifacts\obj\Microsoft.CodeAnalysis.Compilers.Setup.arm64\Debug\net472\Microsoft.CodeAnalysis.Compilers.arm64.vsix
30>Microsoft.CodeAnalysis.Workspaces.MSBuild.UnitTests -> D:\github\roslyn\artifacts\bin\Microsoft.CodeAnalysis.Workspaces.MSBuild.UnitTests\Debug\net472\Microsoft.CodeAnalysis.Workspaces.MSBuild.UnitTests.dll