Use a live crossgen2 always (#59447)

Author: jkoritzinsky

eng/tools/GenerateFiles/Directory.Build.targets.in

@@ -105,10 +105,10 @@
         Condition=" '%(TargetFramework)' == '${DefaultNetCoreTargetFramework}' ">${MicrosoftAspNetCoreAppRuntimeVersion}</AspNetCorePackVersion>
     </KnownAspNetCorePack>
 
-    <KnownCrossgen2Pack Update="Microsoft.NETCore.App.Crossgen2" Condition=" '$(DotNetBuildSourceOnly)' == 'true' ">
+    <KnownCrossgen2Pack Update="Microsoft.NETCore.App.Crossgen2">
       <Crossgen2PackVersion
           Condition=" '%(TargetFramework)' == '${DefaultNetCoreTargetFramework}' ">${MicrosoftNETCoreAppRuntimeVersion}</Crossgen2PackVersion>
-      <Crossgen2RuntimeIdentifiers>$(TargetRuntimeIdentifier)</Crossgen2RuntimeIdentifiers>
+      <Crossgen2RuntimeIdentifiers Condition=" '$(DotNetBuildSourceOnly)' == 'true' ">$(TargetRuntimeIdentifier)</Crossgen2RuntimeIdentifiers>
     </KnownCrossgen2Pack>
 
     <KnownILLinkPack Update="Microsoft.NET.ILLink.Tasks" Condition=" '$(DotNetBuildSourceOnly)' == 'true' ">