Change IllegalArgumentException to ArgumentError.

utils/tests/pub/version_test.dart

 // 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.
 
 #library('version_test');
 
 #import('../../../pkg/unittest/unittest.dart');
 #import('../../pub/utils.dart');
 #import('../../pub/version.dart');
 
@@ skipping 409 matching lines @@
   }
 }
 
 Matcher allows(List<Version> versions) =>
     new VersionConstraintMatcher(versions, true);
 
 Matcher doesNotAllow(List<Version> versions) =>
     new VersionConstraintMatcher(versions, false);
 
 throwsIllegalArg(function) {
-  expect(function, throwsA((e) => e is IllegalArgumentException));
+  expect(function, throwsA((e) => e is ArgumentError));
 }