NH-3372: Enabled use of generated properties in combination with custom ...

...loader.

When a column is specified as generated, the AsbtractEntityPersister always generates SELECT statements to read the generated data. This does not work well when the entities are loaded with a named query by specifying a <loader> element in the entity mapping.
 
The solution is to fall back to reloading the entity using the named query if generated properties must be read.