Remove old isolate API and update all code in the repository to use

tests/isolate/isolate_import_negative_test.dart

Index: tests/isolate/isolate_import_negative_test.dart
diff --git a/tests/isolate/isolate_import_negative_test.dart b/tests/isolate/isolate_import_negative_test.dart
index 80e43421cfc6621efc35c9eaea6e5ff7edfabd24..6ca469512321abee0c95da1b47915e829747c0c1 100644
--- a/tests/isolate/isolate_import_negative_test.dart
+++ b/tests/isolate/isolate_import_negative_test.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, 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.
 
@@ -6,13 +6,9 @@
 // Ommiting the following import is an error:
 // #import('dart:isolate');
 
-class A extends Isolate {
-  A() : super();
-
-  void main() {}
-}
+void entry() {}
 
 main() {
-  new A();
+  spawnFunction(entry);
 }