Remove dotnet8 feeds from NuGet.config (dotnet#95860)

Author: akoeplinger

NuGet.config

@@ -18,8 +18,6 @@
     <add key="dotnet-libraries" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-libraries/nuget/v3/index.json" />
     <!-- Required for System.CommandLine SB intermediate -->
     <add key="dotnet-libraries-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-libraries-transport/nuget/v3/index.json" />
-    <add key="dotnet8" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8/nuget/v3/index.json" />
-    <add key="dotnet8-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8-transport/nuget/v3/index.json" />
     <add key="dotnet9" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet9/nuget/v3/index.json" />
     <add key="dotnet9-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet9-transport/nuget/v3/index.json" />
   </packageSources>

src/installer/tests/Assets/TestUtils/TestProjects.targets

@@ -4,27 +4,27 @@
     provides basic info needed for restore and build with the vanilla SDK.
   -->
 
-  <!-- TODO: Remove when the SDK understands the net8.0 tfm. -->
+  <!-- TODO: Remove when the SDK understands the net9.0 tfm. -->
   <PropertyGroup>
     <NETCoreAppMaximumVersion>9.0</NETCoreAppMaximumVersion>
   </PropertyGroup>
 
   <ItemGroup>
     <KnownFrameworkReference Include="Microsoft.NETCore.App"
-                             DefaultRuntimeFrameworkVersion="8.0.0-rc.1.23415.6"
-                             LatestRuntimeFrameworkVersion="8.0.0-rc.1.23415.6"
+                             DefaultRuntimeFrameworkVersion="9.0.0-alpha.1.23615.3"
+                             LatestRuntimeFrameworkVersion="9.0.0-alpha.1.23615.3"
                              RuntimeFrameworkName="Microsoft.NETCore.App"
                              RuntimePackNamePatterns="Microsoft.NETCore.App.Runtime.**RID**"
                              RuntimePackRuntimeIdentifiers="linux-arm;linux-arm64;linux-musl-arm64;linux-musl-x64;linux-x64;osx-x64;rhel.6-x64;tizen.4.0.0-armel;tizen.5.0.0-armel;win-arm64;win-x64;win-x86;linux-musl-arm;osx-arm64;maccatalyst-x64;maccatalyst-arm64;linux-s390x;linux-bionic-arm;linux-bionic-arm64;linux-bionic-x64;linux-bionic-x86"
                              TargetFramework="$(NetCoreAppCurrent)"
                              TargetingPackName="Microsoft.NETCore.App.Ref"
-                             TargetingPackVersion="8.0.0-rc.1.23415.6"
+                             TargetingPackVersion="9.0.0-alpha.1.23615.3"
                              Condition="'@(KnownFrameworkReference)' == '' or !@(KnownFrameworkReference->AnyHaveMetadataValue('TargetFramework', '$(NetCoreAppCurrent)'))" />
 
     <KnownAppHostPack Include="Microsoft.NETCore.App"
                       ExcludedRuntimeIdentifiers="android"
                       AppHostPackNamePattern="Microsoft.NETCore.App.Host.**RID**"
-                      AppHostPackVersion="8.0.0-rc.1.23415.6"
+                      AppHostPackVersion="9.0.0-alpha.1.23615.3"
                       AppHostRuntimeIdentifiers="linux-arm;linux-arm64;linux-musl-arm64;linux-musl-x64;linux-x64;osx-x64;rhel.6-x64;tizen.4.0.0-armel;tizen.5.0.0-armel;win-arm64;win-x64;win-x86;linux-musl-arm;osx-arm64;linux-s390x;linux-bionic-arm;linux-bionic-arm64;linux-bionic-x64;linux-bionic-x86"
                       TargetFramework="$(NetCoreAppCurrent)"
                       Condition="'@(KnownAppHostPack)' == '' or !@(KnownAppHostPack->AnyHaveMetadataValue('TargetFramework', '$(NetCoreAppCurrent)'))" />