## What changes were proposed in this pull request?
After PruneFileSourcePartitions rule, It needs reset table's statistics because PruneFileSourcePartitions can filter some unnecessary partitions. So the statistics need to be changed.

## How was this patch tested?
add unit test.

Author: lianhuiwang <lianhuiwang09@gmail.com>

Closes #18205 from lianhuiwang/SPARK-20986.