Fix restoring of contexts in inlined finally code

tests/language/regress_22822_test.dart

+// Copyright (c) 2015, 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.
+
+// Regression test for issue 22822. The assignment in the finally block
+// used to crash because it was executed at context level 1 instead of
+// context level 2.
+
+import 'package:expect/expect.dart';
+
+test(b) {
+  try {
+    for (int i = 0; i < 10; i++) {
+      // Closurizing i and b, thus the return statement
+      // executes at context level 2, and the code in
+      // the finally block runs at context level 1.
+      return () => i + b;
+    }
+  } finally {
+    b = 10;
+  }
+}
+
+main() {
+  var c = test(0);
+  Expect.equals(10, c());
+}