Add tests for handling closures in LocalInitializers

pkg/kernel/testcases/closures_initializers/local_initializers.dart

+// Copyright (c) 2017, 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.
+
+// The purpose of this test is to detect that closures in [LocalInitializer]s
+// are properly converted.  This test assumes that
+// [ArgumentExtractionForRedirecting] transformer was run before closure
+// conversion.  It should introduce one [LocalInitializer] for each argument
+// passed to the redirecting constructor.  If such argument contains a closure,
+// it would appear in a [LocalInitializer].
+
+class X {}
+
+class A {
+  X foo;
+  A.named(X foo) {}
+  A(X foo) : this.named((() => foo)());
+}
+
+main() {
+  A a = new A(new X());
+  a.foo; // To prevent dartanalyzer from marking [a] as unused.
+}