Remove AsyncError with Expando.

tests/standalone/io/http_redirect_test.dart

Index: tests/standalone/io/http_redirect_test.dart
diff --git a/tests/standalone/io/http_redirect_test.dart b/tests/standalone/io/http_redirect_test.dart
index f1460838909703c3d8f211f69fb776fceff29828..adcd6c331c737d68f17e1bf6a692e97f9c03491b 100644
--- a/tests/standalone/io/http_redirect_test.dart
+++ b/tests/standalone/io/http_redirect_test.dart
@@ -329,8 +329,8 @@ void testAutoRedirectLimit() {
 
     client.getUrl(Uri.parse("http://127.0.0.1:${server.port}/1"))
       .then((HttpClientRequest request) => request.close())
-      .catchError((e) {
-        Expect.equals(5, e.error.redirects.length);
+      .catchError((error) {
+        Expect.equals(5, error.redirects.length);
         server.close();
         client.close();
       }, test: (e) => e is RedirectLimitExceededException);
@@ -344,8 +344,8 @@ void testRedirectLoop() {
     int redirectCount = 0;
     client.getUrl(Uri.parse("http://127.0.0.1:${server.port}/A"))
       .then((HttpClientRequest request) => request.close())
-      .catchError((e) {
-        Expect.equals(2, e.error.redirects.length);
+      .catchError((error) {
+        Expect.equals(2, error.redirects.length);
         server.close();
         client.close();
       }, test: (e) => e is RedirectLoopException);