RFR 8223065: Add jcmd to get the listen address of the debugger

[Schmelter, Ralf]

Hi David,

good catch. I've moved the vm->native transition back to the start of the method and instead do a native->vm transition before calling print_debug_listen_address() method.

webrev: http://cr.openjdk.java.net/~rschmelter/webrevs/8223065/webrev.2/

Best regards,
Ralf