[VMR] Light up NativeAOT OSX short lanes (#19355)

Author: directhex

src/SourceBuild/content/Directory.Build.props

@@ -30,6 +30,8 @@
     <ShortStack Condition="'$(TargetOS)' == 'maccatalyst'">true</ShortStack>
     <ShortStack Condition="'$(TargetOS)' == 'android'">true</ShortStack>
     <ShortStack Condition="'$(TargetOS)' == 'linux-bionic'">true</ShortStack>
+    <!-- NativeAOT Mac builds are short -->
+    <ShortStack Condition="'$(TargetOS)' == 'osx' and '$(DotNetBuildRuntimeNativeAOTRuntimePack)' == 'true'">true</ShortStack>
     <!-- Short stack builds stop at runtime, not the whole SDK -->
     <RootRepo Condition="'$(ShortStack)' == 'true'">runtime</RootRepo>
   </PropertyGroup>