Increase `highWaterMark` for `CSVWriter`'s queuing strategy

Increase `highWaterMark` for `CSVWriter`'s queuing strategy

This change improves the 100MB Write benchmark from ~9s to ~7s.

Bumping `highWaterMark` to >1 also changes the stream's interaction with `AbortController`, so now the chunk processed during an abort is included in the write.

I believe this behavior has to do with the task queue order of the callback for the `AbortSignal`'s `abort` event - so now with multiple chunks in the queue, the last chunk is written before the `abort` event is processed. I was unable to force this writing code to occur after the `abort` event in a deterministic way.

This situation is a rare edge case so letting it through.