Remove configure-option-dependent test cases from dblink tests.

The HINTs generated for these error cases vary across builds.  We
could try to work around that, but the test cases aren't really useful
enough to justify taking any trouble.

Per buildfarm.

contrib/dblink/expected/dblink.out

@@ -783,14 +783,6 @@ SELECT dblink_disconnect('dtest1');
 
 -- test foreign data wrapper functionality
 CREATE USER dblink_regression_test;
-CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
-  OPTIONS (invalid 'val');   -- fail, invalid option
-ERROR:  invalid option "invalid"
-HINT:  Valid options in this context are: service, connect_timeout, dbname, host, hostaddr, port, application_name, fallback_application_name, keepalives, keepalives_idle, keepalives_interval, keepalives_count, sslmode, sslcompression, sslcert, sslkey, sslrootcert, sslcrl, requirepeer
-CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
-  OPTIONS (password 'val');  -- fail, can't specify password here
-ERROR:  invalid option "password"
-HINT:  Valid options in this context are: service, connect_timeout, dbname, host, hostaddr, port, application_name, fallback_application_name, keepalives, keepalives_idle, keepalives_interval, keepalives_count, sslmode, sslcompression, sslcert, sslkey, sslrootcert, sslcrl, requirepeer
 CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
   OPTIONS (dbname 'contrib_regression');
 CREATE USER MAPPING FOR public SERVER fdtest

contrib/dblink/sql/dblink.sql

@@ -360,14 +360,8 @@ SELECT dblink_disconnect('dtest1');
 
 -- test foreign data wrapper functionality
 CREATE USER dblink_regression_test;
-
-CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
-  OPTIONS (invalid 'val');   -- fail, invalid option
-CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
-  OPTIONS (password 'val');  -- fail, can't specify password here
 CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw
   OPTIONS (dbname 'contrib_regression');
-
 CREATE USER MAPPING FOR public SERVER fdtest
   OPTIONS (server 'localhost');  -- fail, can't specify server here
 CREATE USER MAPPING FOR public SERVER fdtest;