feat(core): add more debug APIs to inspect the application form a browser

Adds `window.getAllAngularRootElements()`
Adds `ng.coreTokens.ApplicationRef`
Adds `ng.coreTokens.Ngzone`

Closes #7045
Closes #7161

modules/angular2/test/public_api_spec.ts

@@ -1308,6 +1308,7 @@ var NG_CORE = [
   'TestabilityRegistry',
   'TestabilityRegistry.findTestabilityInTree()',
   'TestabilityRegistry.getAllTestabilities()',
+  'TestabilityRegistry.getAllRootElements()',
   'TestabilityRegistry.getTestability()',
   'TestabilityRegistry.registerApplication()',
   'GetTestability:dart',