osmo-gsm-tester trial run-dir: improve structure
A trial is a set of binaries. When a trial is tested, a run dir is created for it, and any number of suites may run in it.
Take a look at what happens when multiple suites or even test cases launch the binaries in a trial: the goal is to easily be able to see which suite+scenario and test case created which configuration files and stdout/stderr for the different binaries: the subdirectories in a run dir that are created to hold config files and outputs for the binaries invoked should be organized in a tree structure that reflect originating suite name, scenario and also test script.
For example, each suite will probably launch at least one osmo-nitb. Instead of having 'osmo-nitb', 'osmo-nitb_2', 'osmo-nitb_3', we should have something like 'sms/sysmo/mo_mt_sms.py/osmo-nitb', 'sms/trx/mo_mt_sms.py/osmo-nitb' etc.