[OpenJDK 2D-Dev] RFR: 8173028: Incorrect processing of supplementary-plane characters in text fields

[Phil Race]

https://bugs.openjdk.java.net/browse/JDK-8173028
http://cr.openjdk.java.net/~prr/8173028/

An off by-one bug in assigning remaining glyphs in the cluster to char 
indices
so that the zero advance gets assigned to latin "a" and it is not a hit 
anymore.

font/layout/swing text regression tests have been run.

-phil.