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

frog/tests/leg/no_duplicate_constructor_body_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.
-
-#import("compiler_helper.dart");
-
-final String CODE = """
-class A {
-  A(String b) { b.length; }
-}
-
-main() {
-  new A("foo");
-}
-""";
-
-main() {
-  String generated = compileAll(CODE);
-  RegExp regexp = new RegExp(@'\$.A = {"":');
-  Iterator<Match> matches = regexp.allMatches(generated).iterator();
-  checkNumberOfMatches(matches, 1);
-}