[WIP] fix(components): do not reinsert nodes during redistribution if they hav...

...e not changed

1. It improves the performance of redistribution by 8-10%.
2. It helps input elements keep the focused state (https://github.com/angular/angular.dart/issues/1444).
What about using https://github.com/dart-lang/bleeding_edge/blob/master/dart/pkg/collection/lib/equality.dart#L72