Support UTF in Angular expressions

Currently the lexer in change detection uses StringWrapper.charCodeAt()

• in Dart it returns s.codeUnitAt() which supports UTF
• in JS it returns str.charCodeAt() which does not support UTF

[stephanrauh]

I’d like to see full UTF-8 support for properties in templates, too. Not every programmer speaks English, and as to my experience, it’s a good idea to use your native language for things like variable and method names. It helps to distinguish between your own entities and the entities defined by the framework. Usually, all the popular names are already reserved by frameworks 😃.

[pkozlowski-opensource]

This issue is still relevant and it is confirmed bug in the latest version of Angular, see: https://stackblitz.com/edit/angular-ivy-nuc4uz?file=src/app/app.component.ts

tl;dr; is that it is all about making non-ASCII characters in Angular expressions:

@Component({
  selector: 'my-app',
  template: '<div>{{ 我的 }} </div>',
})
export class AppComponent  {
  // Chinese character
  我的 = 'Angular';
}