RFR: 8168140: TypedArrays should implement ES6 iterator protocol

[Hannes Wallnöfer]

Please review:

Bug: https://bugs.openjdk.java.net/browse/JDK-8168140
Webrev: http://cr.openjdk.java.net/~hannesw/8168140/webrev.00/

I tried to tweak nasgen to allow me to define the new prototype functions just in the common ArrayBufferView base class, but this turned out to be very complicated so I kept it simple and redundant. 

Thanks,
Hannes