Use Directory.CreateDirectory instead of DirectoryUtility to create t…

…he obj folder (#2774)

src/NuGet.Core/NuGet.Commands/RestoreCommand/Utility/NoOpRestoreUtilities.cs

@@ -238,7 +238,7 @@ private static void PersistDGSpecFile(DependencyGraphSpec spec, RestoreRequest r
                 return;
             }
 
-            DirectoryUtility.CreateSharedDirectory(Path.GetDirectoryName(dgPath));
+            Directory.CreateDirectory(Path.GetDirectoryName(dgPath));
             log.LogVerbose($"Persisting no-op dg to {dgPath}");
             spec.Save(dgPath);
         }