[7uNext] Request for approval for CR 8006593 - Performance and compatibility improvements to hash based Map implementations

[Mike Duigou]

Hello all;

This is a request to integrate CR # 8006593. 

http://cr.openjdk.java.net/~mduigou/JDK-8006593/5/webrev/

The change was reviewed and approved on this core-libs-dev thread:

http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-March/014952.html

This changeset is specific to the 7u implementation--the Java 8 implementation is based upon different assumptions. The change fixes a performance regression introduced in 7u6 (CR#7126277/CR#7118743)

Mike