MDEV 13679 Enabled sequences to be used in DEFAULT

Other changes done to get this to work:
- Added 'internal_tables' to TABLE object to list which sequence tables
  is needed to use the table.
- Mark any expression using DEFAULT() with LEX->default_used.
  This is needed when deciding if we should open internal sequence
  tables when a table is opened (we don't need to open sequence tables
  if the main table is only used with SELECT).
- Create_and_open_temporary_table() can now also open all internal
  sequence tables.
- Added option MYSQL_LOCK_USE_MALLOC to mysql_lock_tables()
  to force memory allocation to be used with malloc instead of
  memroot.
- Added flag to MYSQL_LOCK to remember if allocation was done with
  malloc or memroot (makes code simpler and safer).
- init_one_table_for_prelocking() now takes argument for what lock to
  use instead of it's a routine or something else.
- Renamed prelocking placeholders to make them more understandable as
  they are now used in more code.
- Changed test in check_lock_and_start_stmt() if found table has correct
  locks. The old test didn't work for tables that has lock
  TL_WRITE_ALLOW_WRITE, which is what sequence tables are using.
- Added VCOL_NOT_VIRTUAL option to ensure that sequence functions can't
  be used with virtual columns
- More sequence tests

sql/sql_base.h

@@ -100,6 +100,7 @@ TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type update,
 */
 #define MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK         0x1000
 #define MYSQL_LOCK_NOT_TEMPORARY		0x2000
+#define MYSQL_LOCK_USE_MALLOC                   0x4000
 /**
   Only check THD::killed if waits happen (e.g. wait on MDL, wait on
   table flush, wait on thr_lock.c locks) while opening and locking table.
@@ -257,6 +258,7 @@ bool open_normal_and_derived_tables(THD *thd, TABLE_LIST *tables, uint flags,
                                     uint dt_phases);
 bool open_tables_only_view_structure(THD *thd, TABLE_LIST *tables,
                                      bool can_deadlock);
+bool open_and_lock_internal_tables(TABLE *table, bool lock);
 bool lock_tables(THD *thd, TABLE_LIST *tables, uint counter, uint flags);
 int decide_logging_format(THD *thd, TABLE_LIST *tables);
 void close_thread_table(THD *thd, TABLE **table_ptr);