Use correct class name (UnsupportedError instead of UnsupportedOperation) in test

tests/standalone/io/link_uri_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.
 
 import 'dart:io';
 
 import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
 
 void testFromUri() {
@@ skipping 16 matching lines @@
     link.deleteSync();
     target.deleteSync();
     temp.deleteSync();
     asyncEnd();
   });
 }
 
 void testFromUriUnsupported() {
   Expect.throws(
       () => new Link.fromUri(Uri.parse('http://localhost:8080/index.html')),
-      (e) => e is UnsupportedOperation);
+      (e) => e is UnsupportedError);
   Expect.throws(() => new Link.fromUri(Uri.parse('ftp://localhost/tmp/xxx')),
-                (e) => e is UnsupportedOperation);
+                (e) => e is UnsupportedError);
   Expect.throws(() => new Link.fromUri(Uri.parse('name#fragment')),
-                (e) => e is UnsupportedOperation);
+                (e) => e is UnsupportedError);
 }
 
 void main() {
   testFromUri();
   testFromUriUnsupported();
 }