Use incoming ILLinkPackVersion (#55469)

* Use incoming ILLinkPackVersion

* Update Directory.Build.targets.in

Author: wtgodbe

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

@@ -101,6 +101,11 @@
       <Crossgen2RuntimeIdentifiers>$(TargetRuntimeIdentifier)</Crossgen2RuntimeIdentifiers>
     </KnownCrossgen2Pack>
 
+    <KnownILLinkPack Update="Microsoft.NET.ILLink.Tasks" Condition=" '$(DotNetBuildSourceOnly)' == 'true' ">
+      <ILLinkPackVersion
+          Condition=" '%(TargetFramework)' == '${DefaultNetCoreTargetFramework}' ">${MicrosoftNETCoreAppRuntimeVersion}</ILLinkPackVersion>
+    </KnownILLinkPack>
+
     <!-- Use the just-built ASP.NET Core shared framework if available except when building product code in servicing. -->
     <KnownFrameworkReference Update="Microsoft.AspNetCore.App" Condition=" $(UpdateAspNetCoreKnownFramework) ">
       <LatestRuntimeFrameworkVersion