ForUTF unittests

The following Fortran modules still miss testing:

• mo_hash_table !64
• mo_iconlib_kind
• mo_io_units
• mo_namelist
• mo_simple_dump
• mo_util_file (tested on C/C++ side)
• mo_util_libc
• mo_util_nml
• mo_util_rusage
• mo_utile_stride !64
• mo_util_string !63 (merged)
• mo_util_system (tested on C/C++ side)
• mo_util_timer !64