chore: add unit test of syncing large streams

[stbrody]

It's a little hard to tell exactly what the root cause of the failure here is and whether or not it's actually IOD. But this test passes consistently if the NUM_STREAMS and NUM_EVENTS_PER_STREAMS constants are set to low values like 10, but fails pretty regularly when set to 101. It also seems to pass more often when set to 100 than to 101, I'm theorizing that an odd (and prime) number makes the recon conversation more likely to return things out of order compared to an even number. So I think there are reasonable enough odds that this failing due to IOD issues. I guess we'll have to wait until IOD ships and see if this test starts passing to be sure.