Review request for JDK-4487672 (proxy) Proxy constructor should check for null argument

[Mandy Chung]

Please review the simple change for:
  JDK-4487672 (proxy) Proxy constructor should check for null argument

Webrev at:
http://cr.openjdk.java.net/~mchung/jdk8/webrevs/4487672/webrev.00/

Thanks
Mandy