range-diff: fix regression in passing along diff options

range-diff: fix regression in passing along diff options

In 73a834e9e2 ("range-diff: relieve callers of low-level configuration
burden", 2018-07-22) we broke passing down options like --no-patch,
--stat etc.

Fix that regression, and add a test asserting the pre-73a834e9e2
behavior for some of these diff options.

As noted in a change leading up to this ("range-diff doc: add a
section about output stability", 2018-11-07) the output is not meant
to be stable. So this regression test will likely need to be tweaked
once we get a "proper" --stat option.

See
https://public-inbox.org/git/nycvar.QRO.7.76.6.1811071202480.39@tvgsbejvaqbjf.bet/
for a further explanation of the regression. The fix here is not the
same as in Johannes's on-list patch, for reasons that'll be explained
in a follow-up commit.

The quoting of "EOF" here mirrors that of an earlier test. Perhaps
that should be fixed, but let's leave that up to a later cleanup
change.

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