Insert/Load overwrite table partition does not clean up directory before overwriting

When insert/load overwrite table statement containing static partitions, the table directory is not cleaned for partitions not in metastore but exist in the filesystem. This happens in the following cases:

1. External table with external.table.purge set to false: when partition is dropped from the table but partition files exist in the filesystem

2. Files are manually added to a new partition in the file system