Fixed some race conditons and bugs related to killed queries

KILL now breaks locks inside InnoDB
Fixed possible deadlock when running INNODB STATUS
Added ha_kill_query() and kill_query() to send kill signal to all storage engines
Added reset_killed() to ensure we don't reset killed state while awake() is getting called


include/mysql/plugin.h:
  Added thd_mark_as_hard_kill()
include/mysql/plugin_audit.h.pp:
  Added thd_mark_as_hard_kill()
include/mysql/plugin_auth.h.pp:
  Added thd_mark_as_hard_kill()
include/mysql/plugin_ftparser.h.pp:
  Added thd_mark_as_hard_kill()
sql/handler.cc:
  Added ha_kill_query() to send kill signal to all storage engines
sql/handler.h:
  Added ha_kill_query() and kill_query() to send kill signal to all storage engines
sql/log_event.cc:
  Use reset_killed()
sql/mdl.cc:
  use thd->killed instead of thd_killed() to abort on soft kill
sql/sp_rcontext.cc:
  Use reset_killed()
sql/sql_class.cc:
  Fixed possible deadlock in INNODB STATUS by not getting thd->LOCK_thd_data if it's locked.
  Use reset_killed()
  Tell storge engines that KILL has been sent
sql/sql_class.h:
  Added reset_killed() to ensure we don't reset killed state while awake() is getting called.
  Added mark_as_hard_kill()
sql/sql_insert.cc:
  Use reset_killed()
sql/sql_parse.cc:
  Simplify detection of killed queries.
  Use reset_killed()
sql/sql_select.cc:
  Use reset_killed()
sql/sql_union.cc:
  Use reset_killed()
storage/innobase/handler/ha_innodb.cc:
  Added innobase_kill_query()
  Fixed error reporting for interrupted queries.
storage/xtradb/handler/ha_innodb.cc:
  Added innobase_kill_query()
  Fixed error reporting for interrupted queries.

sql/sp_rcontext.cc

@@ -419,7 +419,7 @@ sp_rcontext::activate_handler(THD *thd,
     /* Reset error state. */
 
     thd->clear_error();
-    thd->killed= NOT_KILLED; // Some errors set thd->killed
+    thd->reset_killed();          // Some errors set thd->killed
                                   // (e.g. "bad data").
 
     /* Return IP of the activated SQL handler. */