Eliminate old style import from language tests

tests/language/library6.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.
 
 // This tests that it is a compile-time error to both import a library
 // that defines a function type alias and to have a local definition for
 // another function type alias with the same name.
 // This name conflict is considered an error even if Fun is never referred to.
 
-#library("Library6NegativeTest.dart");
-#import("library5a.dart");  // Defines function type alias Fun
+library Library6NegativeTest.dart;
+import "library5a.dart";  // Defines function type alias Fun
 
 typedef int Fun();  // Does not conflict with definition of Fun from library5a
 
 main() {
 }