title: Angular 5 router doesn't match when query params added
body: <pre><code>I have Angular 5 routes config like this: 
  const loginRoutes: Routes = [
    {
      path: '',
      component: RegistationComponent,
      children: [
        { path: '', redirectTo: 'sign-in', pathMatch: 'full' },
        { path: 'sign-in', component: SigninComponent },
        { path: 'sign-up', pathMatch: 'prefix', component: SignupComponent },
        { path: 'twofactor', component: TwofactorComponent },
      ]
    }
  ];
  </code></pre>
  
  <p>It works well if I browse the exact route, but when I added the query params, says: </p>
  
  <p><a href="http://localhost:4200/login/reg/sign-up?inviteCode=b8f496ca68a37c174459" rel="nofollow noreferrer">http://localhost:4200/login/reg/sign-up?inviteCode=b8f496ca68a37c174459</a></p>
  
  <p>it will redirect back to <code>sign-in</code> route. How do I fix this?</p>