a misnamed function
  ... in the presence of a continue handler. The problem was that with a
  handler, it continued to execute as if function existed and had set a
  useful return value (which it hadn't).
  The fix is to set a null return value and do an error return when a function
  wasn't found.


mysql-test/r/sp.result:
  Updated results for a new test case (BUG#18787).
mysql-test/t/sp.test:
  New testcase for BUG#18787.
sql/item_func.cc:
  Don't set "out of resources" error in Item_func_sp::execute() if no
  result field is returned, it's simply wrong, it can be sometthing else,
  like a function not found. Instead set null_value and return error.
  Also, set "out of resources" when field creation fails in
  Item_func_sp::sp_result_field() and Item_func_sp::tmp_table_field().