Avoid integer underflow and wasted iterations in ToPagedEnumerable.

[extraes]

SearchClient.ToPagedEnumerable can underflow remaining if result.Total and result.Count are different (particularly, if count is greater than total), leading to the paginator asking for a bunch of empty pages at absurd offsets.

This has actually happened, as a heap dump from a running bot confirmed that the remaining variable was 0xFFFFFFFE (4,294,967,294 in decimal, or 0 - 2 in math).

And to avoid wasting iterations on empty responses, in case someone intentionally puts a huge offset in, just yield break when receiving an empty count.

[nickelc]

Thank you for the changes.

I pushed them as bb293a5 and dfcf196.