--single-transaction hack to pg_upgrade does not work

Some of the buildfarm members are failing the pg_upgrade regression test
since commit 12ee6ec71f8754ff3573711032b9b4d5a764ba84. I can duplicate
it here, and the symptom is:

pg_restore: creating TYPE float8range
pg_restore: creating TYPE insenum
pg_restore: [archiver (db)] Error while PROCESSING TOC:
pg_restore: [archiver (db)] Error from TOC entry 978; 1247 16584 TYPE insenum tgl
pg_restore: [archiver (db)] could not execute query: ERROR: ALTER TYPE ... ADD cannot run inside a transaction block
Command was:
-- For binary upgrade, must preserve pg_type oid
SELECT binary_upgrade.set_next_pg_type_oid('16584'::pg_catalog.oid);

I have not investigated why it apparently passes some places; this looks
to me like a guaranteed failure.

regards, tom lane