LimitOffsetPagedList add getTotalCount cache

[spinachomes]

I suggest LimitOffsetPagedList.java cache getTotalCount method result, so getList method may directly return empty list to avoid an unnecessary query when getTotalCount had done and It's result is equal to Zero.

[rbygrave]

Not sure about this in that it's designed to be able to run the 2 queries in parallel. So I don't think it's worth it. If you want to prepare a PR for what you were thinking about I'd have a look?

Edit: Ok, got it - TLDR when totalRowCount has already been determined and is 0 then we can skip finding the list and return an empty collection for this case.