refactor(@schematics/angular): replace deprecated schematic test call

Author: clydin

packages/schematics/angular/interceptor/index_spec.ts

@@ -36,7 +36,7 @@ describe('Interceptor Schematic', () => {
   };
   let appTree: UnitTestTree;
   beforeEach(async () => {
-    appTree = schematicRunner.runSchematic('workspace', workspaceOptions);
+    appTree = await schematicRunner.runSchematicAsync('workspace', workspaceOptions).toPromise();
     appTree = await schematicRunner.runSchematicAsync('application', appOptions, appTree).toPromise();
   });