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/

How did this arrive at 30 seconds?