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.

mysql-test/r/subselect.result:
  The test suite added.
mysql-test/r/subselect_no_mat.result:
  The test suite added.
mysql-test/r/subselect_no_opts.result:
  The test suite added.
mysql-test/r/subselect_no_semijoin.result:
  The test suite added.
mysql-test/r/subselect_scache.result:
  The test suite added.
mysql-test/t/subselect.test:
  The test suite added.
sql/item_cmpfunc.cc:
  Swap arguments creation methods added.
sql/item_cmpfunc.h:
  Swap arguments creation methods added.
sql/item_subselect.cc:
  Swap arguments of the comparison.