fix(router): disallow component routes with named outlets

Closes #11208, #11082

modules/@angular/router/test/config.spec.ts

@@ -7,6 +7,7 @@
  */
 
 import {validateConfig} from '../src/config';
+import {PRIMARY_OUTLET} from '../src/shared';
 
 describe('config', () => {
   describe('validateConfig', () => {
@@ -80,6 +81,16 @@ describe('config', () => {
           .toThrowError(
               /Invalid configuration of route 'a': pathMatch can only be set to 'prefix' or 'full'/);
     });
+
+    it('should throw when pathPatch is invalid', () => {
+      expect(() => { validateConfig([{path: 'a', outlet: 'aux', children: []}]); })
+          .toThrowError(
+              /Invalid route configuration of route 'a': a componentless route cannot have a named outlet set/);
+
+      expect(() => validateConfig([{path: 'a', outlet: '', children: []}])).not.toThrow();
+      expect(() => validateConfig([{path: 'a', outlet: PRIMARY_OUTLET, children: []}]))
+          .not.toThrow();
+    });
   });
 });