ALL subquery should return TRUE if subquery rowa set is empty independently
  of left part.  The problem was that Item_func_(eq,ne,gt,ge,lt,le) do not
  call execution of second argument if first is NULL no in this case subquery
  will not be executed and when Item_func_not_all calls any_value() of the
  subquery or aggregation function which report that there was rows. So for
  NULL < ALL (SELECT...) result was FALSE instead of TRUE.
  
  Fix is just swapping of arguments of Item_func_(eq,ne,gt,ge,lt,le) (with
  changing the operation if it is needed) so that result will be the same
  (for examole a < b is equal to b > a). This fix exploit the fact that
  first argument will be executed in any case.