HMR - Services bootstrapped multiple times, but never torn down #708

Environment

• CLI: 5.0.0

• Cross-platform modules:
  ✔ Component nativescript has 5.0.0 version and is up to date.
  ✔ Component tns-core-modules has 5.0.2 version and is up to date.
  ✔ Component tns-android has 5.0.0 version and is up to date.
  ✔ Component tns-ios has 5.0.0 version and is up to date.

• Android Runtime: 5.0.0

• iOS Runtime: 5.0.0

• Plugin(s): None

• Node.js: 10.12.0

• Please, attach your package.json and webpack.config.js as these configurations are usually critical for investigating issues with webpack.

These are default out of the box configs from using tns create

Describe the bug
When HMR tears down the Angular platform on changes, it correctly calls ngOnDestroy for all components etc, however it does not for services, meaning your app can end up in a weirdly initialized state with multiple "singletons" running side by side.

To Reproduce
tns create - create a new angular project with say, the tabbed view.
Insert a constructor in app/core/data.service.ts: constructor() { console.log("DataService constructor"); }
tns run android --hmr - the app starts, "DataService constructor" is written in console as expected.
Change some text in home.component.html that will cause a refresh. "DataService constructor" gets output again.

Expected behavior
ngOnDestroy is a valid lifecycle hook for services as well, as mentioned here: https://angular.io/api/core/OnDestroy

A lifecycle hook that is called when a directive, pipe, or service is destroyed.

You can imagine the trouble you can get in when you start including Rx Observable subscriptions in the constructor of a service, and even more when services start bootstrapping plugins.

So ngOnDestroy should also get called for services.