[DDC-2931] testcase to reproduce Jira 2931
DDC-2931 - cleaning up code formatting/simplifying test case
DDC-2931 - Detailed explanation
DDC-2931 - Removing refresh hints when fetching association data in hydrators
DDC-2931 - removing old comments
DDC-2931 - adding test that verifies that fetch-joined entities get refreshed with hints
DDC-2931 - Safe comparison between proxies and entities when refreshing objects
DDC-2931 - Removing previous broken fix for DDC-2931 - hardened
Merge pull request #917 from doctrine/hotfix/DDC-2931

DDC-2931 - one-to-one self-referencing association broken by DCOM-96