Improve metadata bwc test - FDW

[jeeminso]

Summary of the changes / Why this is an improvement

Relates #341

Checklist

• Link to issue this PR refers to (if applicable): Fixes #???

[jeeminso]

Noticed that CrateDB allows to CREATE SERVER but provide host/port of its own, and allow creating a foreign table of local table. But should not be a problem, other than hard to figure out what was going on.

[seut]

Noticed that CrateDB allows to CREATE SERVER but provide host/port of its own, and allow creating a foreign table of local table. But should not be a problem, other than hard to figure out what was going on.

It's expected behaviour that the crate user can create a foreign table against itself, see the note at https://cratedb.com/docs/crate/reference/en/latest/admin/fdw.html#jdbc.