test rename overhaul: step 8 - language tests

tests/language/private_member3_negative_test.dart

 // 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.
 
 #library('PrivateMemberLibA');
 
-#import('PrivateMember3LibB.dart');
+#import('private_member3_lib_b.dart');
 
 class A {}
 
 class Test extends B {
   test() {
     _fun();
   }
 }
 
 void main() {
   new Test().test();
 }