RFR JDK-8181425: Reflection API defend against issues with internal VM derived value type

[Mandy Chung]

http://cr.openjdk.java.net/~mchung/valhalla/webrevs/8181425/webrev.00/index.html

This patch changes Class::forName to not to return DVT classes
and also disallows reflection API get members of a DVT class.
ClassLoader::loadClass should probably be changed and I can
fix that separately.

I added a couple of new tests and also fix the MVT tests with
GPL header rather than GPL+CP header.

Mandy