perf: coalesce batches before sending to distributor channels in RepartitionExec#22010

gabotechs wants to merge 3 commits intomainapache/datafusion:mainfrom

gabotechs/repartition-coalesce-batches-berfore-channelsapache/datafusion:gabotechs/repartition-coalesce-batches-berfore-channelsCopy head branch name to clipboard