MDEV-27675 review fixup

rtree_mbr_from_wkb::n_node: Change the data type from int to uint16_t
and pack it together with the added field key_len. In this way, an
increase of sizeof(rtree_mbr_from_wkb) will be avoided.

Author: dr-m

storage/innobase/gis/gis0geo.cc

@@ -445,7 +445,7 @@ pick_next(
 	double*			g1,		/*!< in: mbr of group 1. */
 	double*			g2,		/*!< in: mbr of group 2. */
 	rtr_split_node_t**	choice,		/*!< out: the next node.*/
-	int*			n_group,	/*!< out: group number.*/
+	uint16_t*		n_group,	/*!< out: 1 or 2 */
 	int			n_dim)		/*!< in: dimensions. */
 {
 	rtr_split_node_t*	cur = node;
@@ -487,7 +487,7 @@ mark_all_entries(
 /*=============*/
 	rtr_split_node_t*	node,		/*!< in/out: split nodes. */
 	int			n_entries,	/*!< in: entries number. */
-	int			n_group)	/*!< in: group number. */
+	uint16_t		n_group)	/*!< in: 1 or 2 */
 {
 	rtr_split_node_t*	cur = node;
 	rtr_split_node_t*	end = node + n_entries;
@@ -522,7 +522,7 @@ split_rtree_node(
 	double*			g1 = reserve_coords(d_buffer, n_dim);
 	double*			g2 = reserve_coords(d_buffer, n_dim);
 	rtr_split_node_t*	next = NULL;
-	int			next_node = 0;
+	uint16_t		next_node = 0;
 	int			i;
 	int			first_rec_group = 1;
 	rtr_split_node_t*	end = node + n_entries;

storage/innobase/include/gis0geo.h

@@ -70,9 +70,9 @@ rtree_mbr_from_wkb(
 struct rtr_split_node_t
 {
 	double	square;		/* square of the mbr.*/
-	int	n_node;		/* which group in.*/
-	uchar*	key;		/* key. */
+	uint16_t n_node;	/* group: 1 or 2, or 0=unassigned */
 	uint16_t key_len;	/* key length */
+	uchar*	key;		/* key. */
 	double* coords;		/* mbr. */
 };