Remove the stub "bootstrap" method from AngularDart.
Remove the stub "bootstrap" method from AngularDart.

... and "hide bootstrap" from client code, it is no longer needed.

PiperOrigin-RevId: 191307697

chalin/angular2,matanlurey/angular,matanlurey/angular,angulardart/angular,angulardart/angular,angulardart/angular,chalin/angular2,matanlurey/angular,chalin/angular2