[segmentation.test] Update test histograms

...ams/models/histograms_lwnet_chasedb1_first_annotator.json

...ata/histograms/models/histograms_lwnet_drive_default.json

...ata/histograms/models/histograms_lwnet_iostar_vessel.json

...sts/data/histograms/models/histograms_lwnet_stare_ah.json

...ts/data/histograms/raw_data/histograms_drive_default.json

...ts/data/histograms/raw_data/histograms_iostar_vessel.json

...n/tests/data/histograms/raw_data/histograms_stare_ah.json