[SPARK-13803] restore the changes in SPARK-3411

## What changes were proposed in this pull request?

This patch contains the functionality to balance the load of the cluster-mode drivers among workers

This patch restores the changes in https://github.com/apache/spark/pull/1106 which was erased due to the merging of https://github.com/apache/spark/pull/731

## How was this patch tested?

test with existing test cases

Author: CodingCat <zhunansjtu@gmail.com>

Closes #11702 from CodingCat/SPARK-13803.