Fix double readyForQuery

[brianc]

This is fixing a double readyForQuery message being sent from the backend (because we were calling sync after an error, which I already fixed in the main driver). I also pulled in the reproduction case for another error from #2333, and I'm going to work on fixing that one as well.

[brianc]

Included a test case for #2333 to reproduce the issue and then turned the test green. The issue was a queued stream which the client had not submitted was having an error triggered on it when .end was called on the client. The client errors out all waiting queries if you .end the client while there are queued queries. The entire query queue concept is an unfortunate API decision I made like 9 years ago & it causes all sorts of confusing problems like this. I'd like to remove the ability to queue queries at some point in the future. It doesn't make a lot of sense to me as you're queuing up a bunch of stuff that may or may not work in the future depending on future states & makes the API a bunch more complicated. A lot of this was before there were things like async/await (or even before the async library was widely used) as a "convenience" thing which...yeah...bad idea. The problem w/ removing it is it's a subtle & large-ish breaking change and also a ton of my early unit and integration tests rely on the behavior. So, will be a big undertaking to remove it. Anyways - this fixes another weird edge cases w/ queued query canceling.