BUG #16689: timetz test fails 2020-11-01

The following bug has been logged on the website:

Bug reference: 16689
Logged by: Bernhard M. Wiedemann
Email address: githubbmw2020(at)lsmod(dot)de
PostgreSQL version: 12.4
Operating system: openSUSE-Tumbleweed
Description:

timetz test fails after 2020-11-01
likely from upcoming daylight saving time changes in the US

diff -U3
/home/abuild/rpmbuild/BUILD/postgresql-12.4/src/test/regress/expected/timetz.out
/home/abuild/rpmbuild/BUILD/postgresql-12.4/src/test/regress/results/timetz.out
---
/home/abuild/rpmbuild/BUILD/postgresql-12.4/src/test/regress/expected/timetz.out
2020-08-10 21:15:53.000000000 +0000
+++
/home/abuild/rpmbuild/BUILD/postgresql-12.4/src/test/regress/results/timetz.out
2035-11-30 21:20:50.205175526 +0000
@@ -94,25 +94,25 @@
SELECT '23:59:59.999999'::timetz;
timetz
--------------------
- 23:59:59.999999-07
+ 23:59:59.999999-08
(1 row)

SELECT '23:59:59.9999999'::timetz; -- rounds up
timetz
-------------
- 24:00:00-07
+ 24:00:00-08
(1 row)

SELECT '23:59:60'::timetz; -- rounds up
timetz
-------------
- 24:00:00-07
+ 24:00:00-08
(1 row)

SELECT '24:00:00'::timetz; -- allowed
timetz
-------------
- 24:00:00-07
+ 24:00:00-08
(1 row)

SELECT '24:00:00.01'::timetz; -- not allowed
+ exit 1

To reproduce on Debian or openSUSE:
osc checkout openSUSE:Factory/postgresql12 && cd $_
osc build --vm-type=kvm --noservice --build-opt=--vm-custom-opt="-rtc
base=2020-11-01T08:00:00" standard

Background:
As part of my work on reproducible builds for openSUSE, I check that
software still gives identical build results in the future.
This showed up failing tests in our package build. Then I bisected the
failure date.