Apply the optimization to DocValuesFieldExistsQuery over the field (now deprecated in favor of FieldExistsQuery)

[bowenlan-amzn]

Coming from #11083 (comment)

When a range query's range covers the values of a shard, it will be rewritten into an ExistsQuery on the same field. For our optimization, we should be able to handle this situation and treat it same as the MatchAllDocsQuery case.