Improve portability of the "runtime" system test

The "runtime" system test currently fails on Windows because it waits for named to log a message indicating successful startup ("running"), but that never happens since named on Windows fails to open the configuration file as its path includes control characters.

Instead of putting control characters in directory names, put them in the value of the -D command line switch passed to named, which is used for identifying an instance of named in a process listing and whose value is completely ignored by named, but still logged.

While a similar check using special characters appears to be working fine on Windows for the time being, modify it in the same way to avoid potential future problems on other platforms and make the test cleaner.

Closes #1310 (closed)