Post #35606 cleanup

Author: ViktorHofer

src/libraries/restore/runtime/runtime.depproj

@@ -75,7 +75,7 @@
       <ReferenceCopyLocalPaths Include="@(RuntimeFiles)" />
       <!-- Setup runtime pack native. -->
       <ReferenceCopyLocalPaths Include="@(MonoCrossFiles)"
-                               DestinationSubDirectory="cross" />
+                               DestinationSubDirectory="cross/" />
       <ReferenceCopyLocalPaths Include="@(MonoIncludeFiles)"
                                DestinationSubDirectory="include/%(RecursiveDir)" />
     </ItemGroup>