RFR JDK-8233527: Update Lookup::hasPrivateAccess and Lookup::defineClass spec w.r.t. full power lookup

[Mandy Chung]

This is a follow-up of JDK-8226916. Lookup::hasPrivateAccess intends to 
test if this lookup is a full-power lookup; that is created by the 
original caller class calling MethodHandles::lookup. The current 
specification for Lookup::hasPrivateAccess returns true if the lookup 
modes contain PRIVATE but it does not check MODULE bit.

This patch also clarifies the capabilities w.r.t PRIVATE access and 
full-power access. The security permission check is performed if the 
Lookup is not a full power lookup and therefore Lookup::defineClass spec 
should be updated to perform security permission check if the security 
manager is present and this lookup refuses access, consistent with other 
Lookup operations.

http://cr.openjdk.java.net/~mchung/jdk14/8233527/webrev.02/
http://cr.openjdk.java.net/~mchung/jdk14/8233527/specdiff/

CSR: https://bugs.openjdk.java.net/browse/JDK-8233726

thanks
Mandy