RFR: 8223880: Update sun/net/ftp/FtpURL.java and sun/net/ftp/FtpURLConnectionLeak.java to work with IPv6 addresses

[Daniel Fuchs]

Hi,

Some recent test stabilization fixes had a side effect on
two FTP tests: now that the client might use the IPv6 loopback,
the test might fail on IPv6 only hosts if the test server
doesn't support the extended EPSV mode, or if the client
isn't configured to use NO_PROXY and the default proxy selector
doesn't bypass [0:0:0:0:0:0:0:1] - as happened on my local
machine.

I'd like to push this change that fixes two of the FTP
test recently modified to work with IPv6 addresses as an example
of what might need to be done to get such tests working on
IPv6 only hosts.

http://cr.openjdk.java.net/~dfuchs/webrev_8223880/webrev.00/

JBS: https://bugs.openjdk.java.net/browse/JDK-8223880

best regards,

-- daniel