pgsql: Revert pg_relation_check_pages()

Revert pg_relation_check_pages()

This reverts the following set of commits, following complaints about
the lack of portability of the central part of the code in bufmgr.c as
well as the use of partition mapping locks during page reads:
c780a7a9
f2b88396
b787d4ce
ce7f772c
60a51c6b

Per discussion with Andres Freund, Robert Haas and myself.

Bump catalog version.

Discussion: https://postgr.es/m/20201029181729.2nrub47u7yqncsv7@alap3.anarazel.de

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/e152506adef4bc503ea7b8ebb4fedc0b8eebda81

Modified Files
--------------
doc/src/sgml/func.sgml | 56 --------
src/backend/catalog/system_views.sql | 9 --
src/backend/storage/buffer/bufmgr.c | 92 -------------
src/backend/utils/adt/Makefile | 1 -
src/backend/utils/adt/pagefuncs.c | 229 -------------------------------
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_proc.dat | 7 -
src/include/storage/bufmgr.h | 3 -
src/test/recovery/t/022_page_check.pl | 231 --------------------------------
src/test/regress/expected/pagefuncs.out | 72 ----------
src/test/regress/parallel_schedule | 2 +-
src/test/regress/serial_schedule | 1 -
src/test/regress/sql/pagefuncs.sql | 41 ------
src/tools/pgindent/typedefs.list | 1 -
14 files changed, 2 insertions(+), 745 deletions(-)