Fix heat_map_image prototype to match return type
Fix heat_map_image prototype to match return type

The "output_rows" parameter could modify the set of returned rows.  Make the logic for this in getPrototype() match the logic in getReturnType().
aishwaryarajagopal/Vertica-Extension-Packages,aishwaryarajagopal/Vertica-Extension-Packages,aishwaryarajagopal/Vertica-Extension-Packages,aishwaryarajagopal/Vertica-Extension-Packages