InetAddress.java (toString): Use hostname when not null, don't do an explicit reverse getHostName() lookup.

        * java/net/InetAddress.java (toString): Use hostname when not null,
        don't do an explicit reverse getHostName() lookup.
        * java/net/Socket.java (setSocketImplFactory): When fac == null throw
        NullPointerException.

From-SVN: r59902