Remove deprecated parts of dart:async.

tests/standalone/io/https_server_test.dart

Index: tests/standalone/io/https_server_test.dart
diff --git a/tests/standalone/io/https_server_test.dart b/tests/standalone/io/https_server_test.dart
index a574206be11e8753a66d0f805e9722090381c311..e2f7136e1616e50e71a92ad7a69e151cf63019d3 100644
--- a/tests/standalone/io/https_server_test.dart
+++ b/tests/standalone/io/https_server_test.dart
@@ -43,9 +43,8 @@ void testListenOn() {
                 onDone();
               });
         })
-        .catchError((e) {
+        .catchError((e, trace) {
           String msg = "Unexpected error in Https client: $e";
-          var trace = getAttachedStackTrace(e);
           if (trace != null) msg += "\nStackTrace: $trace";
           Expect.fail(msg);
         });