perf(Forms): Remove all uses of `.runtimeType` from AngularDart.
perf(Forms): Remove all uses of `.runtimeType` from AngularDart.

PiperOrigin-RevId: 175064252

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