pgsql: Set PD_ALL_VISIBLE and visibility map bits in COPY FREEZE

Set PD_ALL_VISIBLE and visibility map bits in COPY FREEZE

Make sure COPY FREEZE marks the pages as PD_ALL_VISIBLE and updates the
visibility map. Until now we only marked individual tuples as frozen,
but page-level flags were not updated, so the first VACUUM after the
COPY FREEZE had to rewrite the whole table.

This is a fairly old patch, and multiple people worked on it. The first
version was written by Jeff Janes, and then reworked by Pavan Deolasee
and Anastasia Lubennikova.

Author: Anastasia Lubennikova, Pavan Deolasee, Jeff Janes
Reviewed-by: Kuntal Ghosh, Jeff Janes, Tomas Vondra, Masahiko Sawada,
             Andres Freund, Ibrar Ahmed, Robert Haas, Tatsuro Ishii,
             Darafei Praliaskouski
Discussion: https://postgr.es/m/CABOikdN-ptGv0mZntrK2Q8OtfUuAjqaYMGmkdU1dCKFtUxVLrg@mail.gmail.com
Discussion: https://postgr.es/m/CAMkU%3D1w3osJJ2FneELhhNRLxfZitDgp9FPHee08NT2FQFmz_pQ%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/7db0cd2145f2bce84cac92402e205e4d2b045bf2

Modified Files
--------------
contrib/pg_visibility/expected/pg_visibility.out | 64 ++++++++++++++++++++
contrib/pg_visibility/sql/pg_visibility.sql      | 77 ++++++++++++++++++++++++
src/backend/access/heap/heapam.c                 | 77 +++++++++++++++++++++---
src/backend/access/heap/hio.c                    | 17 ++++++
src/include/access/heapam_xlog.h                 |  3 +
5 files changed, 230 insertions(+), 8 deletions(-)