Do not generate a compile-time error if there is more than one catch-all clause

tests/language/throw7_test.dart

Index: tests/language/throw7_test.dart
===================================================================
--- tests/language/throw7_test.dart	(revision 28964)
+++ tests/language/throw7_test.dart	(working copy)
@@ -1,16 +0,0 @@
-// Copyright (c) 2011, 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
-
-main() {
-  int i = 0;
-  try {
-    i = 1;
-  } catch (exception) {
-    i = 2;
-  }
-  // Since there is a generic 'catch all' statement preceding this
-  // we expect to get a dead code error/warning over here.
-  on Exception catch (exception) { i = 3; }  /// 01: compile-time error
-}