Review request: 8004260: dynamic proxy class should have same class access as proxy interfaces

[Mandy Chung]

Dynamic proxy class is specified to be public, final, and not
abstract.  For a proxy class that implements a non-public interface,
it will be in the same package as the non-public interface
but the proxy class is accessible outside of the non-public
interface's runtime package. This change will make dynamic proxy
class to have the same Java language access as the proxy interfaces
so that creating a proxy instance to implement a non-public interface
will be guarded by the Java language access check.

Webrev at:
http://cr.openjdk.java.net/~mchung/jdk8/webrevs/8004260/webrev.00/

Specdiff at:
http://cr.openjdk.java.net/~mchung/jdk8/webrevs/8004260/specdiff/overview-summary.html 


This change also updates the spec to specify the permission checks
by Proxy.getProxyClass and Proxy.newProxyInstance methods and removes
the system properties which provide a workaround for 7u releases and
not needed in jdk8.

Thanks
Mandy