change_streams_resume_at_same_clustertime.js should not assume change order

As originally written, change_streams_resume_at_same_clustertime.js assumed that an update performed across two shards to a document on each shard would result in changes with the same cluster time. This is not the case and SERVER-39900 adjusted the test to reflect. When making that adjustment we missed removing assertions that the two documents are returned in a specific order.