RFR: 8003246: Add Supplier to ThreadLocal

[Akhil Arora]

This patch adds a constructor to ThreadLocal to supply initial values 
using the new Supplier functional interface. Please review. This work 
was done by Jim Gish.

http://cr.openjdk.java.net/~akhil/8003246.0/webrev/
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8003246
Thanks