RFR 8036630: Null ProtectionDomain in JVM can cause NPE because principals field is not initialized to an empty array

[Coleen Phillimore]

Summary: Call ProtectionDomain constructor instead of making all fields 
null.

bug link https://bugs.openjdk.java.net/browse/JDK-8036630

hotspot change:

open webrev at http://cr.openjdk.java.net/~coleenp/8036630/

Tested with jdk/test/java/security, and jck lang, vm, and api/java_lang 
tests, and manual test.

Thanks,
Coleen