Eliminate old style import from language tests

tests/language/private_member3_lib_b.dart

Index: tests/language/private_member3_lib_b.dart
===================================================================
--- tests/language/private_member3_lib_b.dart	(revision 15598)
+++ tests/language/private_member3_lib_b.dart	(working copy)
@@ -2,9 +2,9 @@
 // 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('PrivateMemberLibB');
+library PrivateMemberLibB;
 
-#import('private_member3_negative_test.dart');
+import 'private_member3_negative_test.dart';
 
 class B extends A {
   bool _fun() { return true; }