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

tests/language/src/NativeClassIsCheck1FrogTest.dart

Index: tests/language/src/NativeClassIsCheck1FrogTest.dart
diff --git a/tests/language/src/NativeClassIsCheck1FrogTest.dart b/tests/language/src/NativeClassIsCheck1FrogTest.dart
deleted file mode 100644
index 535dcec43ccce9c3cfb58c0c54f715fe7a70b977..0000000000000000000000000000000000000000
--- a/tests/language/src/NativeClassIsCheck1FrogTest.dart
+++ /dev/null
@@ -1,45 +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.
-
-// Test for correct simple is-checks on hidden native classes.
-
-interface I {
-  I read();
-  write(I x);
-}
-
-// Native implementation.
-
-class A implements I native "*A" {
-  // The native class accepts only other native instances.
-  A read() native;
-  write(A x) native;
-}
-
-makeA() native;
-
-void setup() native """
-// This code is all inside 'setup' and so not accesible from the global scope.
-function A(){}
-A.prototype.read = function() { return this._x; };
-A.prototype.write = function(x) { this._x = x; };
-makeA = function(){return new A};
-""";
-
-class B {}
-
-main() {
-  setup();
-
-  var a1 = makeA();
-  var ob = new Object();
-
-  Expect.isFalse(ob is I);
-  Expect.isFalse(ob is A);
-  Expect.isFalse(ob is B);
-
-  Expect.isTrue(a1 is I);
-  Expect.isTrue(a1 is A);
-  Expect.isTrue(a1 is !B);
-}