dart2dart: Support for inner functions in new IR.

tests/language/closure_variable_shadow_test.dart

 // Copyright (c) 2014, 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";
 
-class Foo<T> {
-    reify() {
-        return T;
+// The intermediate variable 'y' must either be preserved 
+// or parameters must be renamed.
+
+foo(x) {
+    var y = x;
+    bar(x) {
+        return y - x;
     }
+    return bar;
 }
 
 main() {
-    Expect.equals(int, new Foo<int>().reify());
-    Expect.equals(Foo, new Foo().runtimeType);
+    Expect.equals(-10, foo(10)(20));
 }