Clean up some pg_dump tests

Clean up some pg_dump tests

1) Remove useless entries from "unlike" lists.  Runs that are not
   listed in "like" don't need to be excluded in "unlike".

2) Ensure there is always a "like" list, even if it is empty.  This
   makes the test more self-documenting.

3) Use predefined lists such as %full_runs where appropriate, instead
   of listing all runs separately.

Also add code that checks 1 and 2 automatically and dies with an error
for violations.

Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://www.postgresql.org/message-id/flat/1f8cb371-e84e-434e-0367-6b716fb16fa1@eisentraut.org