beaker-tests: put nanosecond into project name
    
    The runtest.sh and runtest-fork.sh files both create
    '${NAME_PREFIX}Project10' and '${NAME_PREFIX}Project10Fork' projects
    which - when executed by `all-in-tmux.sh` script - resulted in exactly
    the same project names created by concurrent test runners.  One of the
    runs sometimes failed.
    
    Merges: #1019