JDK-8250630 introduced the following change:

     if (listenAddr == NULL) {
  + // No address of preferred addres family found, grab the fist one.
  + listenAddr = &(addrInfo[0]);
  + }
  +
  + if (listenAddr == NULL) {
         dbgsysFreeAddrInfo(addrInfo);
         RETURN_ERROR(JDWPTRANSPORT_ERROR_INTERNAL, "listen failed: wrong address");
     }

After this change it is no longer possible for the RETURN_ERROR block to ever be executed because listenAddr can not ever still be NULL. The entire block should be removed.

Note this also means that JDK-8248911 can no longer possibly happen.