MDEV-26182 fixes for --ps

* invoke parent's cleanup()
* don't reinit memroot, if already inited (causes memory leak)

also move free_root() from destructor to cleanup() to not accumulate
allocations from prepare and multiple executes

sql/item_jsonfunc.cc

@@ -5207,7 +5207,8 @@ bool Item_func_json_array_intersect::fix_length_and_dec(THD *thd)
     Scan value uses the hash table to get the intersection of two arrays.
   */
 
-  init_alloc_root(PSI_NOT_INSTRUMENTED, &hash_root, 1024, 0, MYF(0));
+  if (!root_inited)
+    init_alloc_root(PSI_NOT_INSTRUMENTED, &hash_root, 1024, 0, MYF(0));
   root_inited= true;
 
   if (json_read_value(&je1) || je1.value_type != JSON_VALUE_ARRAY ||
@@ -5360,7 +5361,8 @@ bool Item_func_json_object_filter_keys::fix_length_and_dec(THD *thd)
 
   json_scan_start(&je2, js2->charset(),(const uchar *) js2->ptr(),
                   (const uchar *) js2->ptr() + js2->length());
-  init_alloc_root(PSI_NOT_INSTRUMENTED, &hash_root, 1024, 0, MYF(0));
+  if (!root_inited)
+    init_alloc_root(PSI_NOT_INSTRUMENTED, &hash_root, 1024, 0, MYF(0));
   root_inited= true;
 
   if (json_read_value(&je2) || je2.value_type != JSON_VALUE_ARRAY ||

sql/item_jsonfunc.h

@@ -902,11 +902,9 @@ class Item_func_json_array_intersect: public Item_str_func
   { return get_item_copy<Item_func_json_array_intersect>(thd, this); }
   void cleanup() override
   {
+    Item_str_func::cleanup();
     if (hash_inited)
       my_hash_free(&items);
-  }
-  ~Item_func_json_array_intersect()
-  {
     if (root_inited)
       free_root(&hash_root, MYF(0));
   }
@@ -934,11 +932,9 @@ class Item_func_json_object_filter_keys: public Item_str_func
 
   void cleanup() override
   {
+    Item_str_func::cleanup();
     if (hash_inited)
       my_hash_free(&items);
-  }
-  ~Item_func_json_object_filter_keys()
-  {
     if (root_inited)
       free_root(&hash_root, MYF(0));
   }