Migrating another batch of tests to dart 2.

tests/language_strong/closure_side_effect_test.dart

-// Copyright (c) 2013, 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 "package:expect/expect.dart";
-
-var b;
-var a = () {
-  b = 42;
-};
-
-var c = [new C()];
-
-class C {
-  nonInlinable1() {
-    a();
-  }
-
-  nonInlinable2() {
-    var a = () {
-      b = 42;
-    };
-    a();
-  }
-}
-
-testClosureInStaticField() {
-  var temp = c[0];
-  Expect.isNull(b);
-  temp.nonInlinable1();
-  Expect.equals(42, b);
-  b = null;
-}
-
-testLocalClosure() {
-  var temp = c[0];
-  Expect.isNull(b);
-  temp.nonInlinable2();
-  Expect.equals(42, b);
-}
-
-main() {
-  testClosureInStaticField();
-  testLocalClosure();
-}