Switch from (%8sync (%run)) to just (%8sync) or (%8sync-run)

Switch from (%8sync (%run)) to just (%8sync) or (%8sync-run)

This is a major overhaul inspired by the fact that (%8sync-port) never
worked (or at least not since error propagation), because the error
resolution code in (%8sync) was specific to (%run).

* 8sync/agenda.scm (%run, %run-at, %run-delay, %port-request)
  (%port-remove-request): Removed variables.
  (%8sync, %8sync-run, %8sync-run-at, %8sync-run-delay)
  (%8sync-port, %8sync-port-remove): Updated to new pattern.
  (%run-with-return, %8sync-immediate): Rename.
* 8sync/systems/irc.scm (make-basic-irc-handler):
  Update from %8sync-run to %8sync
* tests/test-agenda.scm (run-in-fake-agenda): new helper macro
  (test-%run-and-friends): Updated to work with run-in-fake-agenda,
    and upated several calls
  (talk-about-the-zoo, indirection-remote-func-breaks): Updated