RFR: 8023306 : (xs) Add replace() implementations to TreeMap

[Mike Duigou]

Hello all;

This is a small changeset I have split out from the mostly unrelated 
JDK-8021591. This changeset adds Map.replace(key,value) and 
Map.replace(key,oldValue,newValue) implementations to TreeMap that are more 
efficient that that provided by the defaults in Map.

webrev: http://cr.openjdk.java.net/~mduigou/JDK-8023306/0/webrev/

Cheers,

Mike