[SPARK-20843][CORE] Add a config to set driver terminate timeout

## What changes were proposed in this pull request?

Add a `worker` configuration to set how long to wait before forcibly killing driver.

## How was this patch tested?

Jenkins

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #18126 from zsxwing/SPARK-20843.