gives wrong results". Implement previously missing 
Item_row::cleanup. The bug is not repeatable in 5.0, probably 
due to a coincidence: the problem is present in 5.0 as well.


mysql-test/r/ps.result:
  Update the result file (Bug#16248)
mysql-test/t/ps.test:
  Add a test case for Bug#16248 "WHERE (col1,col2) IN ((?,?)) gives 
  wrong results"
sql/item_row.cc:
  Implement Item_row::cleanup(): we should reset used_tables_cache
  before reexecution of a prepared statement. In case ROW
  arguments contain a placeholder, used_tables_cache has PARAM_TABLE
  bit set in statement prepare. As a result, when executing a statement,
  the condition push down algorithm (make_cond_for_table) would think
  that the WHERE clause belongs to the non-existent PARAM_TABLE and
  wouldn't attach the WHERE clause to any of the real tables, 
  effectively optimizing the clause away.
sql/item_row.h:
  Remove a never used member 'array_holder'. Add declaration for
  Item_row::cleanup.