[PATCH] test-lib.sh: set COLUMNS=80 for --verbose repeatability

Some tests will fail under --verbose because while we've unset COLUMNS
since b1d645b58ac (tests: unset COLUMNS inherited from environment,
2012-03-27), we also look for the columns with an ioctl(..,
TIOCGWINSZ, ...) on some platforms. By setting COLUMNS again we
preempt the TIOCGWINSZ lookup in pager.c's term_columns(), it'll take
COLUMNS over TIOCGWINSZ,

This fixes the t0500-progress-display.sh test when run as:

    ./t0500-progress-display.sh --verbose

It broke because of a combination of the this issue and the progress
output reacting to the column width since 545dc345ebd (progress: break
too long progress bar lines, 2019-04-12). The
t5324-split-commit-graph.sh fails in a similar manner due to progress
output, see [1] for details.

A more narrow fix here would be to only do this in the --verbose mode,
but there's no harm in setting this for everything. If we're not
connected to a TTY the COLUMNS setting won't matter.

See ea77e675e56 (Make "git help" react to window size correctly,
2005-12-18) and ad6c3739a33 (pager: find out the terminal width before
spawning the pager, 2012-02-12) for how the TIOCGWINSZ code ended up
in pager.c

1. http://lore.kernel.org/git/20210624051253.GG6312@szeder.dev (local)

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---

This replaces a more narrow fix in
https://lore.kernel.org/git/patch-1.1-cba5d88ca35-20210621T070114Z-avarab@gmail.com/ (local),
which as SZEDER points out was also needed by another test using the
progress.c code.

 t/test-lib.sh | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/t/test-lib.sh b/t/test-lib.sh
index 54938c64279..1a6ca772d6c 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh

@@ -406,14 +406,15 @@ LANG=C
 LC_ALL=C
 PAGER=cat
 TZ=UTC
-export LANG LC_ALL PAGER TZ
+COLUMNS=80
+export LANG LC_ALL PAGER TZ COLUMNS
 EDITOR=:
 
 # A call to "unset" with no arguments causes at least Solaris 10
 # /usr/xpg4/bin/sh and /bin/ksh to bail out.  So keep the unsets
 # deriving from the command substitution clustered with the other
 # ones.
-unset VISUAL EMAIL LANGUAGE COLUMNS $("$PERL_PATH" -e '
+unset VISUAL EMAIL LANGUAGE $("$PERL_PATH" -e '
 	my @env = keys %ENV;
 	my $ok = join("|", qw(
 		TRACE

-- 
2.32.0.605.g06ef811e153