Remove not used fields from ZLIST

parse.y

@@ -11538,9 +11538,6 @@ static rb_node_zlist_t *
 rb_node_zlist_new(struct parser_params *p, const YYLTYPE *loc)
 {
     rb_node_zlist_t *n = NODE_NEWNODE(NODE_ZLIST, rb_node_zlist_t, loc);
-    n->not_used = 0;
-    n->not_used2 = 0;
-    n->not_used3 = 0;
 
     return n;
 }

rubyparser.h

@@ -515,10 +515,6 @@ typedef struct RNode_LIST {
 
 typedef struct RNode_ZLIST {
     NODE node;
-
-    VALUE not_used;
-    VALUE not_used2; /* Used by p->exits */
-    VALUE not_used3; /* Used by p->exits */
 } rb_node_zlist_t;
 
 typedef struct RNode_VALUES {