Some thread statuses related to replication were not included in the
all_server_stages[] array.  That resulted in
performance_schema.threads showing NULL in the PROCESSLIST_STATUS
column (but SHOW PROCESSLIST showed the correct status).  Fixed by
including these thread statuses in the array.

Additionally:
- Changed "Waiting for slave workers to finish." to "Waiting for slave
  workers to process their queues".
- Changed "Waiting for GTID to be written to the binary log" to
  "Waiting for GTID to be committed"
- Changed "Waiting for its turn to commit." to "Waiting for preceding
  transaction to commit"
- Changed "Waiting for dependent transaction to commit." to "Waiting
  for dependent transaction to commit"

Tests:
- mysql-test/suite/rpl/t/rpl_mts_logical_clock_crash.test failed
  becuase it was waiting for
  stage_slave_waiting_for_workers_to_finish.  Fixed the test.  Also
  noticed that despite there was a timeout in wait_condition.inc, it
  just printed a message and continued running the test; it did not
  source show_rpl_debug_info.inc and did not execute 'die'.  Added
  call to show_rpl_debug_info.inc if $show_rpl_debug_info is set (also
  in some other include/wait_*.inc files), and made rpl_init.inc set
  $show_rpl_debug_info.