[SPARK-19292][SQL] filter with partition columns should be case-insensitive on Hive tables

## What changes were proposed in this pull request?

When we query a table with a filter on partitioned columns, we will push the partition filter to the metastore to get matched partitions directly.

In `HiveExternalCatalog.listPartitionsByFilter`, we assume the column names in partition filter are already normalized and we don't need to consider case sensitivity. However, `HiveTableScanExec` doesn't follow this assumption. This PR fixes it.

## How was this patch tested?

new regression test

Author: Wenchen Fan <wenchen@databricks.com>

Closes #16647 from cloud-fan/bug.