Revert "Ensure that failure to start an isolate all end up in the future."

tests/isolate/isolate_create_error_helper_echo.dart

Index: tests/isolate/isolate_create_error_helper_echo.dart
diff --git a/tests/isolate/isolate_create_error_helper_echo.dart b/tests/isolate/isolate_create_error_helper_echo.dart
deleted file mode 100644
index b0231083c60a6d908a7e9b4ce92abbae3ff22347..0000000000000000000000000000000000000000
--- a/tests/isolate/isolate_create_error_helper_echo.dart
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-/// Echo library reports its successful creation as an echo response.
-library isolate.create.error.helper.echo;
-
-import "dart:isolate";
-
-void main(args, port) {
-  for (String s in args) port.send(s);
-}