RFR [13] 8225214: Socket.getOption(SocketOption) not returning the expected type for the StandardSocketOptions.SO_LINGER

[Chris Hegarty]

Please review this change to fix a bug in the handling of SO_LINGER in
the plain socket impl, when setting or retrieving the option through
the new-style setOption or getOption, respectively. The implementation
of the new-style option just delegates to the old-style implementation,
but the old-style has some conversation logic to translate between
negative integral values and boolean false. The new-style implementation
should expect and translate as required.

Webrev:
  https://cr.openjdk.java.net/~chegar/8225214/webrev.00/
Bug:
  https://bugs.openjdk.java.net/browse/JDK-8225214
  
-Chris.