Arcyd: update repo_test2.cfg, require touch files

Assert that try and ok filenames are non-empty in reporeporter.
Require try and ok filenames in abdcmd_single.

Test Plan: testbed/arcyd/ $ ./run_arcyd_multi.sh
Rethink Arcyd cmds: remove single, multionce

Pave the way for new Arycd commands for rendering html, launching as a
daemon, managing config files.

Remove 'arcyd multionce', it only exists to make testing 'arcyd multi'
easier.  Replace with argument to 'arcyd multi'.

Remove 'arcyd single', it only existed to make exercising Arcyd easier.

Move processargs setup for individual repos out of abdcmd_single to
abdi_processargs.

Move lots of init out of abdcmd_arcyd into abdi_processargs where it can
be explicitly shared as required.

Remove 'old' Arcyd testbed scripts and configs, replace with single
'exercise_arcyd.sh'.

Add new 'process_once' function to phlsys_scheduleunreliables to enable
the '--no-loop' parameter to 'arcyd multi'.
WIP