Use `dart compile js` instead of `dart2js` in bench builders
Use `dart compile js` instead of `dart2js` in bench builders

Dart 2.17 started to give this warning for `dart2js`:

    Warning: The 'dart2js' entrypoint script is deprecated, please use
    'dart compile js' instead.

dart-lang/dart-protobuf,dart-lang/dart-protobuf,google/protobuf.dart,dart-lang/protobuf,dart-lang/dart-protobuf,dart-lang/protobuf,dart-lang/protobuf,google/protobuf.dart,google/protobuf.dart