Simon Heimberg <simohe@besonet.ch> [Thu, 21 Mar 2013 08:56:21 +0100] rev 18788
run-tests: only sort files when not given as argument
os.listdir returns the files in any order. This has to be sorted.
But when given as argument, the user should be allowed to set any order.
This restores the behaviour before 9848a94e2a.