### What changes were proposed in this pull request?
This PR optimizes the RoundRobin algorithm to achieve a more balanced disk slot allocation across workers.
Previously, when allocating 3000 partitions using RoundRobin, the slot distribution across worker disks was [668, 666, 666], which resulted in one disk having 2 more slots than the others.
After the optimization, the slot distribution is now [667, 667, 666], ensuring a more balanced allocation.
### Why are the changes needed?
The changes are necessary to improve load balancing across worker disks, reducing the risk of overloading a single disk. This ensures a more predictable and fair distribution of slots, which can lead to better performance and resource utilization.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
UT
Closes#3074 from gaoyajun02/1843.
Authored-by: gaoyajun02 <gaoyajun02@meituan.com>
Signed-off-by: Shuang <lvshuang.xjs@alibaba-inc.com>
c45197c0c1