Move tests using frog 'native' extension from tests/language to frog/tests

tests/language/src/NativeLibrarySameNameUsedLib2.dart

Index: tests/language/src/NativeLibrarySameNameUsedLib2.dart
diff --git a/tests/language/src/NativeLibrarySameNameUsedLib2.dart b/tests/language/src/NativeLibrarySameNameUsedLib2.dart
deleted file mode 100644
index 6b77dc38316ebe3d882ebcd0399d57a9fcd79194..0000000000000000000000000000000000000000
--- a/tests/language/src/NativeLibrarySameNameUsedLib2.dart
+++ /dev/null
@@ -1,14 +0,0 @@
-// 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('NativeLibrarySameNameUsedLib1.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;
-}