cat-file tests: test for missing/bogus object with -t, -s and -p

cat-file tests: test for missing/bogus object with -t, -s and -p

When we look up a missing object with cat_one_file() what error we
print out currently depends on whether we'll error out early in
get_oid_with_context(), or if we'll get an error later from
oid_object_info_extended().

The --allow-unknown-type flag then changes whether we pass the
"OBJECT_INFO_ALLOW_UNKNOWN_TYPE" flag to get_oid_with_context() or
not.

The "-p" flag is yet another special-case in printing the same output
on the deadbeef OID as we'd emit on the deadbeef_short OID for the
"-s" and "-t" options, it also doesn't support the
"--allow-unknown-type" flag at all.

Let's test the combination of the two sets of [-t, -s, -p] and
[--{no-}allow-unknown-type] (the --no-allow-unknown-type is implicit
in not supplying it), as well as a [missing,bogus] object pair.

This extends tests added in 3e370f9faf0 (t1006: add tests for git
cat-file --allow-unknown-type, 2015-05-03).

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>