Double free on repeated execution of prepared aggregate function against empty table in Query_arena::free_items()

delimiter |;

create aggregate function cnt() returns int

begin

  declare z int default 0;

  declare continue handler for not found return z;

  loop 

    fetch group next row;

    set z = z+1;

  end loop; 

end|

delimiter ;|

create table t1 (id int);

prepare test from "select cnt() from t1";

execute test;

execute test;

==204305==ERROR: AddressSanitizer: heap-use-after-free on address 0x75f356665e60 at pc 0x5e502b7b7168 bp 0x73a34722dbe0 sp 0x73a34722dbd0

READ of size 8 at 0x75f356665e60 thread T5

    #0 0x5e502b7b7167 in Query_arena::free_items() /src/mariadb/sql/sql_class.cc:4192

    #1 0x5e502e2d80e1 in Item_sum_sp::clear() /src/mariadb/sql/item_sum.cc:1449

    #2 0x5e502e380d71 in Aggregator_simple::clear() /src/mariadb/sql/item_sum.h:735

    #3 0x5e502b24526a in Item_sum::aggregator_clear() /src/mariadb/sql/item_sum.h:563

    #4 0x5e502d012e62 in Item_sum::no_rows_in_result() /src/mariadb/sql/item_sum.h:524

    #5 0x5e502bfb2fd2 in return_zero_rows /src/mariadb/sql/sql_select.cc:17875

    #6 0x5e502bed09fc in JOIN::exec_inner() /src/mariadb/sql/sql_select.cc:5014

    #7 0x5e502becb1a8 in JOIN::exec() /src/mariadb/sql/sql_select.cc:4877

...