fixes build errors

src/Umbraco.Tests/TestHelpers/BaseUmbracoApplicationTest.cs

@@ -160,8 +160,7 @@ namespace Umbraco.Tests.TestHelpers
                     var mappers = PluginManager.Current.FindAndCreateInstances<IMapperConfiguration>(
                         specificAssemblies: new[]
                         {
-                            typeof(ContentModelMapper).Assembly,
-                            typeof(ApplicationRegistrar).Assembly
+                            typeof(ContentModelMapper).Assembly
                         });
                     foreach (var mapper in mappers)
                     {

src/Umbraco.Web/Strategies/Migrations/EnsureAppsTreesUpdatedOnUpgrade.cs

@@ -36,7 +36,6 @@ namespace Umbraco.Web.Strategies.Migrations
         void EnsureAppsTreesUpdated_Upgrading(object sender, EnsureAppsTreesUpdated.UpgradingEventArgs e)
         {
             var treeRegistrar = new ApplicationTreeRegistrar();
-            var appRegistrar = new ApplicationRegistrar();
         }
     }
 }

src/umbraco.cms/businesslogic/Packager/Installer.cs

@@ -439,7 +439,6 @@ namespace umbraco.cms.businesslogic.packager
 
                 // Trigger update of Apps / Trees config.
                 // (These are ApplicationStartupHandlers so just instantiating them will trigger them)
-                new ApplicationRegistrar();
                 new ApplicationTreeRegistrar();
 
                 insPack.Save();