Materialized view registry does not clean non existing views at refresh

CBO plans of materialized views which are enabled for query rewrite are cached in HS2 (MaterializedViewsCache, HiveMaterializedViewsRegistry)

The registry is refreshed periodically from HMS:

set hive.server2.materializedviews.registry.refresh.period=1500s;

This functionality is required when multiple HS2 instances are used in a cluster: MV drop operation is served by one of the HS2 instances and the registry is updated at that time in that instance. However other HS2 instances still cache the non-existent view and need to be refreshed by the updater thread.
Currently the updater thread adds new entries, refresh existing ones but does not remove the outdated entries.