Fixed Informix physical naming strategy compatibility

[VladoKuruc]

Some unit tests with Informix are failing because Informix interprets identifiers in lowercase. Setting the physical naming strategy globally for all unit tests also doesn't make sense because many tests have hardcoded expected values. The solution is to change the column mapping in problematic tests to lowercase values to accommodate all dialects.

https://www.ibm.com/docs/en/informix-servers/12.10?topic=variable-specify-field-names

This topic was discussed here: https://hibernate.zulipchat.com/#narrow/stream/132096-hibernate-user/topic/Global.20hibernate.20properties.20for.20unit.20tests