Large amount of memory use for caching ClientPreparedStatement

Since we have updated the connector from 2.7.4 to 3.0.4, we are experimenting some memory leaks, and after some analysis we have found that the cache variable in ClientParser is the main suspect.

There is now a cache for ClientPreparedStatement, inside ClientParser, that variable is a LinkedHashMap and seems to be never cleanse. And there is no known way to interact with this cache. That resolve to store all the prepared statements since the server is started.