The `pg_regress` tests check invalid parameter handling and basic

functionality. They're intended for use by the buildfarm using an in-tree

`make check`, but may also be run with an out-of-tree PGXS build against an

existing PostgreSQL install using `make USE_PGXS=1 clean installcheck`.

The tests may fail on installations that are not utf-8 encoded because the

payloads of the binary protocol output will have text in different encodings,

which aren't visible to psql as text to be decoded. Avoiding anything except