### What changes were proposed in this pull request?
Remove `StatusSystem#handleWorkerRemove` from `RegisterWorker` to avoid duplicated behavior in `RegisterWorker`.
### Why are the changes needed?
`RegisterWorker` has already been improved to cover the behavior of `StatusSystem#handleWorkerRemove`. Therefore, `StatusSystem#handleWorkerRemove` is recommend to remove from `RegisterWorker` for avoiding duplicated behavior in `RegisterWorker`.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
CI.
Closes#2731 from SteNicholas/CELEBORN-932.
Authored-by: SteNicholas <programgeek@163.com>
Signed-off-by: mingji <fengmingxiao.fmx@alibaba-inc.com>