allow dart:* libs to implement otherwise disallowed types (e.g. int)
allow dart:* libs to implement otherwise disallowed types (e.g. int)

all current and experimental Dart implementations (dart2js, vm, fletch, ddc) get an error in their SDK from this. The CL fixes it by allowing dart:* libraries to implement the disallowed types, like int/double/String/bool.

R=brianwilkerson@google.com

Review URL: https://codereview.chromium.org//1346923007 .

dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk