Remove AsyncError with Expando.

pkg/scheduled_test/test/substitute_future_test.dart

Index: pkg/scheduled_test/test/substitute_future_test.dart
diff --git a/pkg/scheduled_test/test/substitute_future_test.dart b/pkg/scheduled_test/test/substitute_future_test.dart
index f9c8b32437f22edb089467ce74c86ddd2d540693..2b70fa2bb75d54d5d49cfcbf26262a135dba5db0 100644
--- a/pkg/scheduled_test/test/substitute_future_test.dart
+++ b/pkg/scheduled_test/test/substitute_future_test.dart
@@ -31,28 +31,28 @@ void main() {
 
     test('.then and .catchError on success', () {
       expect(future.then((v) => "transformed $v")
-              .catchError((e) => "caught ${e.error}"),
+              .catchError((error) => "caught ${error}"),
           completion(equals('transformed success')));
       completer.complete('success');
     });
 
     test('.then and .catchError on error', () {
       expect(future.then((v) => "transformed $v")
-              .catchError((e) => "caught ${e.error}"),
+              .catchError((error) => "caught ${error}"),
           completion(equals('caught error')));
       completer.completeError('error');
     });
 
     test('.then with onError on success', () {
       expect(future.then((v) => "transformed $v",
-              onError: (e) => "caught ${e.error}"),
+              onError: (error) => "caught ${error}"),
           completion(equals('transformed success')));
       completer.complete('success');
     });
 
     test('.then with onError on error', () {
       expect(future.then((v) => "transformed $v",
-              onError: (e) => "caught ${e.error}"),
+              onError: (error) => "caught ${error}"),
           completion(equals('caught error')));
       completer.completeError('error');
     });