and value-list

The server returns unexpected results if a right side of the 
NOT IN clause consists of NULL value and some constants of
the same type, for example:

  SELECT * FROM t WHERE NOT t.id IN (NULL, 1, 2) 
  
may return 3, 4, 5 etc if a table contains these values.


The Item_func_in::val_int method has been modified:
unnecessary resets of an Item_func_case::has_null field 
value has been moved outside of an argument comparison
loop. (Also unnecessary re-initialization of the null_value
field has been moved).