Make Doctrine's dependency injection test less fragile.

[Doctrine][DependencyInjection] The test checks that a few items are ordered according to the value of their 'priority' attribute. However, a few of the items have the same value of this attribute. RegisterEventListenersAndSubscribersPass doesn't use a stable sorting, yet the test asserts that items that are 'equal' shall go in the original order. Modified so that the order of the original items is not checked.