#1008178: remove two core comment tests that fail, one is a real core bug, one is a test that doesn't like caching.

#1050562 and #1008178: by catch, clear persistent cache when  are passed to resetCache, also add tests.

#1008178: remove hook_() implementations since hook_entity_delete() is invoked by core now. Also hook_comment_insert() and hook_comment_update() were redundant.

Start respecting  again, remove hook_entitycache_resolve_conditions() because mongodb_dbtng is a more likely solution to the problem.

When you say implements hook_comment_insert(), don't actually call the implementation hook_comment_insert(), doh.