[teststabilization] RFR: 8231631: sun/net/ftp/FtpURLConnectionLeak.java fails intermittently with NPE

[Daniel Fuchs]

Hi,

Please find below a trivial test fix for:

8231631: sun/net/ftp/FtpURLConnectionLeak.java fails intermittently
          with NPE
https://bugs.openjdk.java.net/browse/JDK-8231631

webrev:
http://cr.openjdk.java.net/~dfuchs/webrev_8231631/webrev.00/

readLine() returns null on EOF - which was mishandled.

best regards,

-- daniel