fix(ivy): support ng-container at the root of a view with delayed insertion

[pkozlowski-opensource]

This PR handles the following case:

<ng-template #tpl>
  <ng-container>
    content
  </ng-container>
</ng-template>

where #tpl is not inserted into the DOM immediately. This might happen where the TemplateRef.createEmbeddedView(...) is called to create view instance and then this view is inserted (or not) at the later time.

[mary-poppins]

You can preview 7bd6b3f at https://pr25329-7bd6b3f.ngbuilds.io/.

[mary-poppins]

You can preview ac14ae3 at https://pr25329-ac14ae3.ngbuilds.io/.

[mhevery]

http://test/OCL:207578950:BASE:207578992:1533580300448:edfaa4d0

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