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

frog/tests/leg_only/int_index_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.
-
-main() {
-  var a = [0, 1];
-  a[1.2];     /// 01: runtime error
-  a[1.2] = 4; /// 02: runtime error
-  checkIndex(a, 1.4); /// 03: runtime error
-  checkIndexedAssignment(a, 1.4); /// 04: runtime error
-  checkIndex(a, 0);
-  checkIndexedAssignment(a, 0);
-}
-
-checkIndex(a, b) {
-  a[b];
-}
-
-checkIndexedAssignment(a, b) {
-  a[b] = 1;
-}