Avoid passing datanode around preparing datanode code directory
refactory.
Also refine unit test code for same component. The `Await` shall return
first before checking the counter number since when lock cost is heavy
(using deadlock.RWMutex See PR #33069.) case may fail due to long
running time submitting tasks.
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>