RFR 8003421: NPG: Move oops out of InstanceKlass into mirror

[Coleen Phillimore]

Summary: Inject protection_domain, signers, init_lock into java_lang_Class

Net footprint change is zero except that these fields are in Java heap 
rather than metaspace.  This helps a little with InstanceKlass size 
which is in fixed size space with UseCompressedKlassPointers. Included 
serviceability because there were SA changes to code that I don't know 
is used.

Future work is to remove the signers field and the unused 
SetProtectionDomain function.

open webrev at http://cr.openjdk.java.net/~coleenp/8003421/
bug link at http://bugs.sun.com/view_bug.do?bug_id=8003421

Tested with vm.quick.testlist, JPRT, jtreg java/security tests and jck8 
tests.

Thanks,
Coleen