Revert Non text modes for pg_dumpall, and pg_restore support

Revert Non text modes for pg_dumpall, and pg_restore support

Recent discussions of the mechanisms used to manage global data have
raised concerns about their robustness and security. Rather than try
to deal with those concerns at a very late stage of the release cycle,
the conclusion is to revert these features and work on them for the
next release.

This reverts parts or all of the following commits:

1495eff7bdb Non text modes for pg_dumpall, correspondingly change pg_restore
5db3bf7391d Clean up from commit 1495eff7bdb
289f74d0cb2 Add more TAP tests for pg_dumpall
2ef57908067 Fix a couple of error messages and tests for them
b52a4a5f285 Clean up error messages from 1495eff7bdb
4170298b6ec Further cleanup for directory creation on pg_dump/pg_dumpall
22cb6d28950 Fix memory leak in pg_restore.c
928394b664b Improve various new-to-v18 appendStringInfo calls
39729ec01d2 Fix fat fingering in 22cb6d28950
5822bf21d50 Add missing space in pg_restore documentation.
f09088a01d3 Free memory properly in pg_restore.c
40b9c27014d pg_restore cleanups
4aad2cb7707 Portability fix: isdigit() must be passed an unsigned char.
88e947136b4 Fix typos and grammar in the code
f60420cff66 doc: Alphabetize long options for pg_dump[all].
bc35adee8d7 doc: Put new options in consistent order on man pages
a876464abc7 Message style improvements
dec6643487b Improve pg_dump/pg_dumpall help synopses and terminology
0ebd2425558 Run pgperltidy

Discussion: https://postgr.es/m/20250708212819.09.nmisch@google.com

Backpatch-to: 18
Reviewed-by: Noah Misch <noah@leadboat.com>