- Simplify collection of stack traces. If we determine that a stack

tests/language/error_stacktrace_test.dart

 // Copyright (c) 2013, 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.
 // Dart test program for testing throw statement
 
 import "package:expect/expect.dart";
 
 class MyException {
   const MyException(String message) : message_ = message;
   final String message_;
@@ skipping 37 matching lines @@
     return func4();
   }
   static int func4() {
     var i = 0;
     try {
       i = 10;
       func5();
     } on ArgumentError catch (e, s) {
       i = 200;
       Expect.isNotNull(e.stackTrace, "Errors need a stackTrace on throw");
-      Expect.isFalse(identical(e.stackTrace, s));
       Expect.equals(e.stackTrace.toString(), s.toString());
     }
     return i;
   }
   static List func5() {
     // Throw an Error.
     throw new ArgumentError("ArgumentError in func5");
   }
 }
 
@@ skipping 34 matching lines @@
   static testMain() {
     Expect.equals(100, Helper1.func1());
     Expect.equals(200, Helper2.func1());
     Expect.equals(300, Helper3.func1());
   }
 }
 
 main() {
   ErrorStackTraceTest.testMain();
 }