message: nydus-test: explicitly set prefetch_all in rafs config
  By default, prefeth_all is true in rafs config. We
  can't verify prefetch table contents then.
diff: @@ -196,13 +196,12 @@ class RafsConf:
  threads_count=8,
  merging_size=128 * 1024,
  bandwidth_rate=0,
  - prefetch_all=None,
  + prefetch_all=False,
  ):
  self._configure_rafs("fs_prefetch.enable", True)
  self._configure_rafs("fs_prefetch.threads_count", threads_count)
  self._configure_rafs("fs_prefetch.merging_size", merging_size)
  self._configure_rafs("fs_prefetch.bandwidth_rate", bandwidth_rate)
  - if prefetch_all is not None:
  self._configure_rafs("fs_prefetch.prefetch_all", prefetch_all)
  return self
  