civicrm_add_domain.mysql broken due to civicrm_payment_processor_type.name being unique

The civicrm_payment_processor_type.name field is UNIQUE, which breaks civicrm_add_domain.mysql - this script tries to create the same set of names for every domain_id.

We should drop the UNIQUE constraint from civicrm_payment_processor_type.name and create an index on name + domain_id.