Remove withConsecutive() in CronQueueTest

Problem/Motivation

PHPUnit is deprecating withConsecutive(), so we need to find replacements.

Steps to reproduce

Proposed resolution

In two cases, we need to assert that two separate messages are logged. To me the order is unimportant as long as the messages are both logged, so we can use Prophecy to do this more easily.

Merge request link

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet