B-56355 - Improve the performance of "last" page

For all requests with marker = "last"
- Removed the SELECT COUNT(*) ... query; now uses default page size for all adapters.
- Ensured/added shouldGetFeedWithLastMarker() test for all adapters.
Merge pull request #255 from usnavi/B-56355_last

B-56355 - Improve the performance of "last" page