Fix testGetMultiResults when there is only unknown K-mer
The previous test was only looking for a single unknown K-mer in the map even though the map shouldn't contain anything else from unknown K-mers. Indeed when there is no K-mers in the automaton that match the input sequence, then the map contains only unknown K-mers. For more informations, see #3303.
feature-a/3303-correct-testgetmultiresults in 28 minutes and 51 seconds (queued for 1 second)8 jobs for