RFR(S) 8219607: Add support in Graal and AOT for hidden class

[Dean Long]

https://bugs.openjdk.java.net/browse/JDK-8219607
http://cr.openjdk.java.net/~dlong/8219607/webrev/

This change adds support for the Class.isHidden() intrinsic to Graal.

thanks,

dl