[#5699] make chunked_find more efficient everywhere by avoiding skip()
[#5699] move utils tests into same file; diff test in its own file
[#5699] don't clobber the sort_key if it's in the query
[#5699] cleanup of unused untested util functions
[#5699] Added more checks to chunked_find test

Signed-off-by: Cory Johns <johnsca@geek.net>