Optimization of queries with DETERMINISTIC functions in the
WHERE clause was not effective: sequential scan was always
used.
Now a SF with the DETERMINISTIC flags is treated as constant
when it's arguments are constants (or a SF doesn't has arguments).


sql/item_func.h:
  Fixed bug #29338.
  The Item_func_sp::used_tables has been removed
  (virtual Item_func::used_tables function is enough).
  The virtual Item_func_sp::update_used_tables function
  has been added.
sql/item_func.cc:
  Fixed bug #29338.
  The Item_func_sp::update_used_tables and the
  Item_func_sp::fix_field functions have been modified
  to take into account the DETERMINISTIC flag of SF definition.
mysql-test/r/sp.result:
  Updated test case for bug #29338.
mysql-test/t/sp.test:
  Updated test case for bug #29338.