c/testsuite.pm: Allow test names with upper case letters

Signed-off-by: Niels Thykier <niels@thykier.net>
c/files.pm: Re-instate dir_counts (it had other callers)

In commit 82079ea, I overlooked two other calls of dir_counts.

Signed-off-by: Niels Thykier <niels@thykier.net>