No large-object test in regression suite?

I don't see one, but I think there ought to be one.

My revised libpq managed to pass the regression tests
even though PQfn() was broken; I didn't discover that
until I tried to run the large-object example in
src/test/example/testlo.c.  (Perhaps that file could
be converted into a regression test with little effort?)

BTW, src/test/example/testlo2.c looks like a waste of
disk space.  It seems to be an old version of testlo.c.

            regards, tom lane