[JBPAPP6-1774] jconsole fails if trying to connect to a standalone EAP i...

...nstance running with offset ports

After this fix JConsole will not throw NullPointerException.  And all the following conditions will run successfully.

1).
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./standalone.sh -Djboss.socket.binding.port-offset=100

JConsole URL
service:jmx:remoting-jmx://localhost:10099


2).
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./standalone.sh -Djboss.socket.binding.port-offset=100 -bmanagement 10.3.238.71

JConsole URL
service:jmx:remoting-jmx://10.3.238.71:10099

3).
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./standalone.sh -bmanagement 10.3.238.71

JConsole URL
service:jmx:remoting-jmx://10.3.238.71:9999


4).
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./standalone.sh 

JConsole URL
service:jmx:remoting-jmx://localhost:9999