euphoria-flink: optimize sort

[horkyada]

Sort consists of sorting elements by a composite key <Window, ExtractedObject>. SortTranslator for flink executor relies on GenericTypeComparator for Window as well as for user defined extracted object which causes a huge performance overhead because of deserializing both objects on every compare.

• we can define our custom TypeComparator for known windows, or just emit NormalizableKey instead of the window
• however without knowing the extracted objects' type we are not able to tune the comparing of those objects