Gremlin VM repeat/until/emit flows do not respect barriers

I detailed some of the information here https://discord.com/channels/838910279550238720/1151590132021997598/1151590132021997598 but the short version of what I have found is that if you have a flow like:

```
g.V().repeat(barrier().out()).until(barrier().out().count().is(P.eq(0))).toList()
```

What ends up happening in the `barrier()` step inside the `until` block will have items trickle in 1 at a time, while the `barrier()` in the `repeat` block will have all the items come in at once. So in otherwords the control flow of the `repeat`/`emit`/`until` flow will not respect barriers injected inside the `until`/`emit` blocks.
https://discord.com/channels/838910279550238720/1151590132021997598/1151590132021997598
In my use case (and the use case I suspect others have) barriers are used heavily in movement which is where these `repeat` flows are often used.