fix wildcard interconnect address type

[Stolb27]

Partially revert 50748b7 changes that broke down wildcard interconnect address type handling for gpdb 7. Removed duplicated assertion, already checked for unicast interconnect few lines above. interconnect_address is null for wildcard address type. In this case service arg of getaddrinfo must not be null, because either node or service may be null according to man page.

A unit test for this case is provided too.

Here are some reminders before you submit the pull request

• [x] Add tests for the change
• [ ] Document changes
• [ ] Communicate in the mailing list if needed
• [x] Pass make installcheck
• [ ] Review a PR in return to support the community

[vmwclabot]

@Stolb27, you must sign our contributor license agreement before your changes are merged. Click here to sign the agreement. If you are a VMware employee, read this for further instruction.

[vmwclabot]

@Stolb27, we have received your signed contributor license agreement. The review is usually completed within a week, but may take longer under certain circumstances. Another comment will be added to the pull request to notify you when the merge can proceed.