[SPARK-21457][SQL] ExternalCatalog.listPartitions should correctly handle partition values with dot

## What changes were proposed in this pull request?

When we list partitions from hive metastore with a partial partition spec, we are expecting exact matching according to the partition values. However, hive treats dot specially and match any single character for dot. We should do an extra filter to drop unexpected partitions.

## How was this patch tested?

new regression test.

Author: Wenchen Fan <wenchen@databricks.com>

Closes #18671 from cloud-fan/hive.