test(ng_model): detect browsers that do not support `simulateTypingText`
test(ng_model): detect browsers that do not support `simulateTypingText`

Detect browsers that do not support `simulateTypingText` and skip tests
that rely on it.

Closes #814

hitesh97/angular.dart,hitesh97/angular.dart,rkirov/angular.dart,winstonewert/angular.dart,ronlobo/angular.dart,SibuStephen/angular.dart,rkirov/angular.dart,SibuStephen/angular.dart,ronlobo/angular.dart,SibuStephen/angular.dart,winstonewert/angular.dart,trinarytree/angular.dart,trinarytree/angular.dart,ronlobo/angular.dart,giovannicandido/angular.dart,rkirov/angular.dart,hitesh97/angular.dart,hitesh97/angular.dart,winstonewert/angular.dart,winstonewert/angular.dart,giovannicandido/angular.dart,ronlobo/angular.dart,SibuStephen/angular.dart,trinarytree/angular.dart,trinarytree/angular.dart,rkirov/angular.dart,giovannicandido/angular.dart