1. Do not initialize dict_table_t::stats_latch in ibuf
2. Remove overengineering in GenericPolicy to speed up things

dict_mem_table_create(): add new argument init_stats_latch

ibuf_dummy_index_create(): do not initialize dict_table_t::stats_latch

GenericPolicy: add new members m_filename and m_line

sync_file_create_register()
sync_file_created_deregister()
sync_file_created_get()
CreateTracker: remove

rw_lock_t::created: a new debug member