Fix handling of 'path/to/file:some_suffix' in test arguments
In qmt (or new pytest) tests, the command line is processed to convert relative paths to absolute paths so that the command works when run from a temporary directory.
The logic didn't take into account that gaudirun.py
does support options arguments like path/to/file.py:function_to_call
. This MR fixes the logic so that also relative paths like this are handled correctly.