Steps to reproduce:
1. Set hibernate.globally_quoted_identifiers and hibernate.id.new_generator_mappings to true.
2. Create an entity with @GeneratedValue(strategy = GenerationType.TABLE) which would force org.hibernate.id.enhanced.TableGenerator to be used as new_generator_mappings is enabled.
3. Create hibernate_sequences table in the database, either manually or by invoking hbm2ddl in update mode.
4. Invoke hbm2ddl in validate mode. It would fail saying that hibernate_sequences table does not exist.