Add missing CleanReturnAsync() to some tests. (#18471)

Content.IntegrationTests/Tests/Body/SaveLoadReparentTest.cs

@@ -157,7 +157,11 @@ public sealed class SaveLoadReparentTest
                         Assert.That(component.ParentSlot.Child, Is.EqualTo(id));
                     });
                 }
+
+                maps.DeleteMap(mapId);
             }
         });
+
+        await pairTracker.CleanReturnAsync();
     }
 }