TPAC: repair staff client End link for showing last record

TPAC: repair staff client End link for showing last record

In the embedded TPAC, when staff clicks the End link in the record
detail page to jump to the last record in the search results, it now
makes an intermediate jump through search code, which locates the last
record in the set (via CGI param find_last) then redirects to the record
detail page for the last record.  With this approach, we don't have to
pre-fetch the entire set of record IDs just to render the paging links.
Tip o' the hat to Mike R. for the design suggestion.

https://bugs.launchpad.net/evergreen/+bug/984070

Signed-off-by: Bill Erickson <berick@esilibrary.com>
Signed-off-by: Ben Shum <bshum@biblio.org>