Revert "Parts must start with 'part of'" and "Attempt to fix VM build"

dart/tests/language/prefix6_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 Prefix6NegativeTest;
-import "library10.dart" as lib10;
+#library("Prefix6NegativeTest.dart");
+#import("library10.dart", prefix:"lib10");
 
 class Prefix6NegativeTest {
   static Test1() {
     // Variables in the local scope hide the library prefix.
     var lib10 = 0;
     var result = 0;
     result += lib10.Library10.static_func();  // This should fail.
   }
 }
 
 main() {
   Prefix6NegativeTest.Test1();
 }