Add char arrays output

[MelReyCG]

As geos::string_array type output as int8 array, we cannot really diagnose changing text data in the integrated tests.
As a temporary solution, I propose to add a character comparison output to the current one.

• The comparison operates on the following characters:

!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ012456789

• To prevent indentation false-positive, all successive whitespaces are merged as one space before comparison.
• Other non-printable characters are ignored and considered as string separators, useful to detect if the string_array could have been only reordered.

As an exemple, for my PR about extending the cellBlocks input (which order the cellBlock names alphabetically), we would have this message in the compositionalMultiphaseFlow/deadoil_3ph_staircase_3d_01 test logs:

********************************************************************************
Error: /Problem/domain/MeshBodies/mesh/meshLevels/Level0/ElementRegions/elementRegionsGroup/Channel/cellBlocks/__values__
        Arrays of types int8 and int8 have 148 values of which 11 have differing values.
        Statistics of the differences greater than 0:
                max_index = (99,), max = 2, mean = 1.0909090909090908, std = 0.28747978728803447
********************************************************************************

And this is what I propose:

********************************************************************************
Error: /Problem/domain/MeshBodies/mesh/meshLevels/Level0/ElementRegions/elementRegionsGroup/Channel/cellBlocks/__values__
        Arrays of types int8 and int8 have 148 values of which 11 have differing values.
        Statistics of the differences greater than 0:
                max_index = (99,), max = 2, mean = 1.0909090909090908, std = 0.28747978728803447
        Differing valid characters (substrings reordering detected):
            cb-1_0_0  cb-0_0_0  cb-0_0_1  cb-0_1_1  cb-0_1_2  cb-1_1_2  cb-1_1_3  cb-1_0_3
            cb-0_0_0  cb-0_0_1  cb-0_1_1  cb-0_1_2  cb-1_0_0  cb-1_0_3  cb-1_1_2  cb-1_1_3
               ^             ^       ^           ^     ^ ^ ^       ^ ^         ^       ^  ********************************************************************************

The "substrings reordering detected" note helps the reader to know that the substrings are only reordered.