Simplify test for heading names
Simplify test for heading names

We were using `to_sentence` to check the order, while it's easier to
just check the exact contents of the array.

Furthermore, using `to_sentence` checked the order of the array, so it
was a potentially flaky spec since the method doesn't specify an order
and PostgreSQL doesn't guarantee the order of the records.

usabi/consul_san_borondon,consul/consul,consul/consul,usabi/consul_san_borondon,consul/consul,usabi/consul_san_borondon,consul/consul,consul/consul,usabi/consul_san_borondon