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

frog/tests/frog_native/native_null_closure_frog_test.dart

-// Copyright (c) 2012, 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.
-
-typedef void MyFunctionType();
-
-class A native "*A" {
-  setClosure(MyFunctionType f) native;
-  check(MyFunctionType f) native;
-  invoke() native;
-}
-
-makeA() native { return new A(); }
-
-void setup() native """
-function A() {}
-A.prototype.setClosure = function(f) { this.f = f; };
-A.prototype.check = function(f) { return this.f === f; };
-A.prototype.invoke = function() { return this.f(); };
-makeA = function(){return new A;};
-""";
-
-
-main() {
-  setup();
-  A a = makeA();
-  a.setClosure(null);
-  Expect.isTrue(a.check(null));
-  bool caughtException = false;
-  try {
-    a.invoke();
-  } catch (Exception e) {
-    caughtException = true;
-  }
-  Expect.isTrue(caughtException);
-}