[OpenJDK 2D-Dev] RFR 8015556 : Supplementary chars broken on macos x

[Phil Race]

http://cr.openjdk.java.net/~prr/8015556/
http://bugs.sun.com/view_bug.do?bug_id=8015556

Supplementary chars are DOA in the OS X port since
the mapper code there is ignorant of them, doing such
things as down-casting an int code point to a char before
doing the lookup and storing the first char of a surrogate pair
as being the map key, not the decoded supplementary char.
Interestingly the key to the map was of type integer so
that part I didn't have to change.

I've run through Font2DTest and SwingSet with this patch.
Since it touches a key part of the code if there's bugs I'd
expect them to show up there. I didn't see any problems
and it improves the supplementary char support.

I expect to back port this to 7u40 since its clearly a major issue,
but there's not much time for it to bake in 8 first, so please
try it out (if you can).

-phil.