22.0-bug_fix-PixelRawDataByteStreamCnv

This should fix the issue seen in ATR-21979, whereby pixel RDOs are seen to be duplicated and this breaks the 8-cell connectivity code recently committed ( !36138 (merged) ). Previously this was thought to occur only in consecutive RDOs and the detection only allowed for this. The fix (due to @oda) introduces an unordered set to also trap non-consecutive but identical RDOs by checking the insertion into that set. A small cleanup was also done, removing commented code (largely dating from 2014).