message: Use shlex to split `--cmd-prefix`
  Summary: It was not necessary before, but be more general and accept more complex prefixes.
diff: @@ -376,7 +376,7 @@ def run_redex_binary(state, term_handler):
  ]
  if state.args.cmd_prefix is not None:
  - args = state.args.cmd_prefix.split() + args
  + args = shlex.split(state.args.cmd_prefix) + args
  if state.args.config:
  args += ["--config", state.args.config]
  