- Added some debug assertions checking that the runtime services
   indexes computed by get_unique_oen() are sane.

 - Do not print the name of the service when its descriptor is
   invalid. If the descriptor is corrupted then its name field
   could be corrupted as well and we would end up reading an
   arbitrary amount of invalid memory.

Change-Id: I16f61065277d01fe1555d5a9cf743f7b52ccaa60