RFR 8146556: jdk.dynalink.beans.ClassLinker can avoid using specific lookup and can use publicLookup instead

[Sundararajan Athijegannathan]

Please review http://cr.openjdk.java.net/~sundar/8146556/webrev/ for 
https://bugs.openjdk.java.net/browse/JDK-8146556

Thanks,
-Sundar