[Tests] clearer comparison of HDF5 files

Working on !931 (merged), I found the comparison of HDF5 files against reference files was not very clear. This aims to show all the differences found, not only the first one (i.e. not asserting on each separate step), to present the results in a clearer format, and to simplify the code doing the comparisons.

Based off the branch in !931 (merged), because I know that fails the relevant tests, so I can see what the results look like.

cc @ahmedk

tests/test_reference_runs/test_pre_deployment.py

@@ -164,9 +164,6 @@ def validate_hdf5_files(
           the reference data to validate against
         cal_type (str): The type of calibration processing.
           e.g. dark or correct.
-        find_difference (bool): A flag indicating a need to find the
-          difference between two files if tested data was
-          not identical to the reference data.
     """
     print("\n--- Compare HDF5 files  ----")
     print("REF:", reference_folder)