name-rev: make dedicated --annotate-stdin --name-only test

name-rev: make dedicated --annotate-stdin --name-only test

The previous commit split the `--name-only` handling:

1. `--annotate-stdin`: uses the new `struct command`
2. The rest: uses `struct name_ref_data`

But there is no dedicated test for the option combination in (1). That
means that the following tests will fail if you neglect to set
`command.u.name_only` properly:

    name-rev --annotate-stdin works with commitGraph
    name-rev --annotate-stdin works with non-monotonic timestamps

even though it has nothing to do with what these tests are supposed
to test.

Let’s add another regression test now that it is relevant.

Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>