Merge changes I0308ddf9,I3227c00e,I76ba1af4,Id27c561a

* changes:
  8u121-b13 integration for java.net - Document Android changes
  Integrate upstream changes forgotten in the update to OpenJDK 8u121-b13
  Remove unncessary hostname assignment in Inet6Address.initif
  Remove DatagramSocket.setNetworkInterface