CQ event might be missing if HAContainer enables eviction

The issue exists when proxies are enqueue cq messages to each HARegionQueue. As HAContainer enables eviction, the value (ClientUpdateMessageImpl) can be evicted. The next proxy needs to fault in the message when enqueues the event to its queue and _clientCqs map is lost during that exchange.

The operation will create a new _clientCqs map in this case, and if a dispatcher thread is processing the already queued event and access the map at the same time, it will not find its client in the cq maps, and thus cause the cq event is lost.