Review request for JDK-8012359 - Increase code coverage in Joni

[Hannes Wallnoefer]

Please review JDK-8012359 - Increase code coverage in Joni:

http://cr.openjdk.java.net/~hannesw/8012359/

This removes most code we do not use in Joni, including regexp features 
not used in ECMAScript, alternative implementations of features, and 
things left over from multibyte encoding support.

I tested with ant test and test262, currently running Node tests.

Hannes