MDEV-23842 Atomic RENAME TABLE

- Major rewrite of ddl_log.cc and ddl_log.h
  - ddl_log.cc described in the beginning how the recovery works.
  - ddl_log.log has unique signature and is dynamic. It's easy to
    add more information to the header and other ddl blocks while still
    being able to execute old ddl entries.
  - IO_SIZE for ddl blocks is now dynamic. Can be changed without affecting
    recovery of old logs.
  - Code is more modular and is now usable outside of partition handling.
  - Renamed log file to dll_recovery.log and added option --log-ddl-recovery
    to allow one to specify the path & filename.
- Added ddl_log_entry_phase[], number of phases for each DDL action,
  which allowed me to greatly simply set_global_from_ddl_log_entry()
- Changed how strings are stored in log entries, which allows us to
  store much more information in a log entry.
- ddl log is now always created at start and deleted on normal shutdown.
  This simplices things notable.
- Added probes debug_crash_here() and debug_simulate_error() to simply
  crash testing and allow crash after a given number of times a probe
  is executed. See comments in debug_sync.cc and rename_table.test for
  how this can be used.
- Reverting failed table and view renames is done trough the ddl log.
  This ensures that the ddl log is tested also outside of recovery.
- Added helper function 'handler::needs_lower_case_filenames()'
- Extend binary log with Q_XID events. ddl log handling is using this
  to check if a ddl log entry was logged to the binary log (if yes,
  it will be deleted from the log during ddl_log_close_binlogged_events()
- If a DDL entry fails 3 time, disable it. This is to ensure that if
  we have a crash in ddl recovery code the server will not get stuck
  in a forever crash-restart-crash loop.

mysqltest.cc changes:
- --die will now replace $variables with their values
- $error will contain the error of the last failed statement

storage engine changes:
- maria_rename() was changed to be more robust against crashes during
  rename.

sql/debug_sync.cc

@@ -1628,3 +1628,74 @@ bool debug_sync_set_action(THD *thd, const char *action_str, size_t len)
 /* prevent linker/lib warning about file without public symbols */
 int debug_sync_dummy; 
 #endif /* defined(ENABLED_DEBUG_SYNC) */
+
+
+/**
+   Debug utility to do crash after a set number of executions
+
+   The user variable, either @debug_crash_counter or @debug_error_counter,
+   is decremented each time debug_crash() or debug_simulate_error is called
+   if the keyword is set with @@debug_push, like
+   @@debug_push="d+frm_data_type_info_emulate"
+
+   If the variable is not set or is not an integer it will be ignored.
+*/
+
+#ifndef DBUG_OFF
+
+static const LEX_CSTRING debug_crash_counter=
+{ STRING_WITH_LEN("debug_crash_counter") };
+static const LEX_CSTRING debug_error_counter=
+{ STRING_WITH_LEN("debug_error_counter") };
+
+static bool debug_decrement_counter(const LEX_CSTRING *name)
+{
+  THD *thd= current_thd;
+  user_var_entry *entry= (user_var_entry*)
+    my_hash_search(&thd->user_vars, (uchar*) name->str, name->length);
+  if (!entry || entry->type != INT_RESULT || ! entry->value)
+    return 0;
+  (*(ulonglong*) entry->value)= (*(ulonglong*) entry->value)-1;
+  return !*(ulonglong*) entry->value;
+}
+
+void debug_crash_here(const char *keyword)
+{
+  DBUG_ENTER("debug_crash_here");
+  DBUG_PRINT("enter", ("keyword: %s", keyword));
+
+  DBUG_EXECUTE_IF(keyword,
+                  if (debug_decrement_counter(&debug_crash_counter))
+                  {
+                    my_printf_error(ER_INTERNAL_ERROR,
+                                    "Crashing at %s",
+                                    MYF(ME_ERROR_LOG | ME_NOTE), keyword);
+                    DBUG_SUICIDE();
+                  });
+  DBUG_VOID_RETURN;
+}
+
+/*
+  This can be used as debug_counter to simulate an error at a specific
+  position.
+
+  Typical usage would be
+  if (debug_simualte_error("keyword"))
+    error= 1;
+*/
+
+bool debug_simulate_error(const char *keyword, uint error)
+{
+  DBUG_ENTER("debug_crash_here");
+  DBUG_PRINT("enter", ("keyword: %s", keyword));
+  DBUG_EXECUTE_IF(keyword,
+                  if (debug_decrement_counter(&debug_error_counter))
+                  {
+                    my_printf_error(error,
+                                    "Simulating error for '%s'",
+                                    MYF(ME_ERROR_LOG), keyword);
+                    DBUG_RETURN(1);
+                  });
+  DBUG_RETURN(0);
+}
+#endif /* DBUG_OFF */