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

tests/language/src/NativeLibrarySameNameUsedLib1.dart

Index: tests/language/src/NativeLibrarySameNameUsedLib1.dart
diff --git a/tests/language/src/NativeLibrarySameNameUsedLib1.dart b/tests/language/src/NativeLibrarySameNameUsedLib1.dart
deleted file mode 100644
index 531270daead5c740c40167936485bc471bea8b56..0000000000000000000000000000000000000000
--- a/tests/language/src/NativeLibrarySameNameUsedLib1.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.
-
-// 'I' is the name of an interface and the name of the native class.
-
-#import('NativeLibrarySameNameUsedLib2.dart');
-
-interface I {
-  I read();
-  write(I x);
-}
-
-makeI() native { new Impl(); }  // Hint Impl is created by makeI.