Simplify visibility check in heap_page_would_be_all_visible()

Simplify visibility check in heap_page_would_be_all_visible()

heap_page_would_be_all_visible() does not need to distinguish between
HEAPTUPLE_RECENTLY_DEAD and HEAPTUPLE_DEAD tuples: any tuple in a state
other than HEAPTUPLE_LIVE means the page is not all-visible and
heap_page_would_be_all_visible() returns false.

Given that, calling HeapTupleSatisfiesVacuum() is unnecessary, since it
performs extra work to distinguish between dead and recently dead tuples
using OldestXmin. Replace it with the more minimal
HeapTupleSatisfiesVacuumHorizon().

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CALdSSPjvhGXihT_9f-GJabYU%3D_PjrFDUxYaURuTbfLyQM6TErg%40mail.gmail.com