[Nestmates] RFR: 8197539: [Nestmates] Revert all changes to VerifyAccess.isSameMemberPackage and Lookup.in behaviour

[David Holmes]

webrev: http://cr.openjdk.java.net/~dholmes/8197539/webrev/

webrev relative to mainline: 
http://cr.openjdk.java.net/~dholmes/8197539/webrev.mainline/

bug: https://bugs.openjdk.java.net/browse/JDK-8197539

After going through the issue in JDK-8197395, there is no need to change 
VerifyAccess.isSameMemberPackage to be aware of nestmates, as nestmates 
will already pass the enclosing class check. So we can restore this code 
to its existing mainline form.

This leaves the legacy behaviour of Lookup.in exactly as it was, and 
adds no special cases for nestmates.

Testing:
   runtime/Nestmates
   java/lang/invoke

Thanks,
David