Fix _bench endpoint specs to have the body on the right level in the json object
Fix _bench endpoint specs to have the body on the right level in the json object

fubuki/elasticsearch,vorce/es-metrics,aparo/elasticsearch,fubuki/elasticsearch,fubuki/elasticsearch,aparo/elasticsearch,aparo/elasticsearch,vorce/es-metrics,aparo/elasticsearch,aparo/elasticsearch,fubuki/elasticsearch,vorce/es-metrics,fubuki/elasticsearch,aparo/elasticsearch,fubuki/elasticsearch,vorce/es-metrics,vorce/es-metrics