Problem with IonicPageModule.

_From @ThunderBirdsX3 on May 15, 2017 4:15_

Reopen from #11550

**Ionic version:** (check one with "x")
[ ] **1.x**
[ ] **2.x**
[x] **3.x**

**I'm submitting a ...** (check one with "x")
[x] bug report
[ ] feature request
[ ] support request => Please do not submit support requests here, use one of these channels: https://forum.ionicframework.com/ or http://ionicworldwide.herokuapp.com/

**Current behavior:**
I try to use `PageModule` for navigation to page. `this.navCtrl.push('Page')` or `this.navCtrl.setRoot('Page')`.
That good, Because I didn't to import page in `app.module.ts`. But when i use command `ionic run ios -l -c` and save or reload app. It stuck in old page.

In `app.component.ts` I set `rootPage:any = 'Loading';`. This `loading.ts` has some logic about check database `SQLlite`. After check data it would take to other page `this.navCtrl.setRoot('Login')` or `this.navCtrl.setRoot('Tabs')` with data from database.

And yes, When i save the code or reload app. It will not load `'Loading'` page first. It will go to last page from `navController` and I will not get data from `Loading` page.

**Expected behavior:**
If I use old way. ( Import page to `app.module.ts`) Every thing is fine. After save the code or reload app. It will start with `Loading` page first. Not stuck in last `navController`.

**Steps to reproduce:**

**Related code:**

Good.
```
this.navCtrl.setRoot(Tabs)
this.navCtrl.push(SomePage)
```

Not good.
```
this.navCtrl.setRoot('Tabs')
this.navCtrl.push('SomePage')
```

**Other information:**
```
global packages:

@ionic/cli-utils : 1.0.0
Cordova CLI : 7.0.0
Ionic CLI : 3.0.0

local packages:

@ionic/app-scripts : 1.3.7
@ionic/cli-plugin-cordova : 1.0.0
@ionic/cli-plugin-ionic-angular : 1.0.0
Ionic Framework : ionic-angular 3.2.0

System:

Node : v6.9.5
OS : macOS Sierra
Xcode : Xcode 8.3.2 Build version 8E2002
ios-deploy : 1.9.1
ios-sim : 5.0.13

```

_Copied from original issue: ionic-team/ionic#11662_

Start by reviewing app.component.ts, loading.ts, and app.module.ts, then reproduce the behavior with ionic run ios -l -c using the string-based navigation examples. Compare startup and navigation when pages are imported versus referenced by name. Done means reloads consistently begin at Loading and still navigate to Login or Tabs with the intended database data.

索引モデルが issue の本文から書いたものです。