[tests/data/histograms] Pretty format

...tograms/models/histograms_alexnet_montgomery_default.json

...ms/models/histograms_densenet-121_montgomery_default.json

...histograms/models/histograms_pasa_montgomery_default.json

tests/data/histograms/raw_data/histograms_hivtb_fold_0.json

...s/data/histograms/raw_data/histograms_indian_default.json

...ta/histograms/raw_data/histograms_montgomery_default.json

...ata/histograms/raw_data/histograms_nih_cxr14_default.json

...s/data/histograms/raw_data/histograms_padchest_idiap.json

...data/histograms/raw_data/histograms_shenzhen_default.json

tests/data/histograms/raw_data/histograms_tbpoc_fold_0.json

...data/histograms/raw_data/histograms_tbx11k_v1_fold_0.json

...data/histograms/raw_data/histograms_tbx11k_v2_fold_0.json