Add test.

tests/language/src/LibraryPrivateInConstructorA.dart

Index: tests/language/src/LibraryPrivateInConstructorA.dart
diff --git a/tests/language/src/LibraryPrivateInConstructorA.dart b/tests/language/src/LibraryPrivateInConstructorA.dart
new file mode 100644
index 0000000000000000000000000000000000000000..51b7001658d2313c6600d364f875ad5dd883c60e
--- /dev/null
+++ b/tests/language/src/LibraryPrivateInConstructorA.dart
@@ -0,0 +1,17 @@
+// 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.
+
+#library('LibraryPrivateInConstructorA');
+
+class PrivateA {
+  const PrivateA();
+  final _val = 499;
+}
+
+var fooA = const PrivateA();
+
+class A {
+  var x;
+  A() : this.x = fooA._val;
+}