Move frog/tests/{leg,leg_only,frog_native} to tests/compiler/.

frog/tests/frog_native/native_library_same_name_used_lib2.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.
-
-// Native implementation.
-
-#library('lib2');
-#import('native_library_same_name_used_lib1.dart');  // To get interface I.
-
-// Native impl has same name as interface.
-class Impl implements I native "*I" {
-  Impl read() native;
-  write(Impl x) native;
-}