HHH-9106 : Merging multiple representations of the same entity (improved logging)

(cherry picked from commit fed3191eb7e4edb3dab7823219540c0d064669b9)
HHH-9234 : Test  failure (testNaturalIdChangedWhileAttached) on SAP/SYBASE ASE

(cherry picked from commit 257efd10254b40a41016ec29d4ee2e90bf6c4d87)
HHH-9106 : (corrected test case to work on MySQL)
HHH-9090 - HQL: parser is trying to reuse parent implied join for subquery

(cherry picked from commit 133f0825a3e97b123b3fb88f7971ced6e20ef600)