pgsql: Adjust createdb TAP tests to work on recent OpenBSD.

Adjust createdb TAP tests to work on recent OpenBSD.

We found last February that the error-case tests added by commit
008cf0409 failed on OpenBSD, because that platform doesn't really
check locale names.  At the time it seemed that that was only an issue
for LC_CTYPE, but testing on a more recent version of OpenBSD shows
that it's now equally lax about LC_COLLATE.

Rather than dropping the LC_COLLATE test too, put back LC_CTYPE
(reverting c4b0edb07), and adjust these tests to accept the different
error message that we get if setlocale() doesn't reject a bogus locale
name.  The point of these tests is not really what the backend does
with the locale name, but to show that createdb quotes funny locale
names safely; so we're not losing test reliability this way.

Back-patch as appropriate.

Discussion: https://postgr.es/m/231373.1610058324@sss.pgh.pa.us

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/c67fea09da25463b6f6fc73fa2676ffd53e9a8e5

Modified Files
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src/bin/scripts/t/020_createdb.pl | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)