Internal: remove IndexCloseListener & Store.OnCloseListener

#8436 has introduced shard level locks in order to prevent directory reuse during fast deletion & creation of indices. As part for the change, close listeners were introduced to delete the folders once all out standing references were released. The new change has created race conditions causing shard folders not to be deleted (causing test failures due to left over corruption markers). This commit removes the listeners in favour of a simple timeout based solution to be use until a better listener based solution is ready ( #8608 ).

Example test failure can be found at: http://build-us-00.elasticsearch.org/job/es_core_master_metal/6120/

That's a good question. The delete index has an ack timeout of 30s (default) and ideally you would like to wait longer than this for the delete not to be acked (we can have a different solution to make sure it's not acked, this is change is meant to small and temporary) but on the other hand not to delay cluster state processing beyond the 30s the master waits to avoid having multiple cluster states in flight. I agree this is not ideal at all but I felt it was good enough as a temporary measure until a proper solution is in place.