HHH-9268 The NoopOptimizer used for default id generation doesn't need synchronization
HHH-9269 Store persister to ReferenceCacheEntryImpl to avoid costly lookup at read time
HHH-8683 Class org.hibernate.engine.spi.EntityEntry consumes lots of memory
HHH-8683 Adding test for setting/getting attributes in compressed state int
HHH-8683 Caching enum constants to avoid memory allocation by repeated calls to getEnumConstants()
HHH-8683 Making EnumState a parameterized class, thus allowing to access its value more safely