revisions API: have release_revisions() release "cmdline"

revisions API: have release_revisions() release "cmdline"

Extend the the release_revisions() function so that it frees the
"cmdline" in the "struct rev_info". This in combination with a
preceding change to free "commits" and "mailmap" means that we can
whitelist another test under "TEST_PASSES_SANITIZE_LEAK=true".

There was a proposal in [1] to do away with xstrdup()-ing this
add_rev_cmdline(), perhaps that would be worthwhile, but for now let's
just free() it.

We could also make that a "char *" in "struct rev_cmdline_entry"
itself, but since we own it let's expose it as a constant to outside
callers. I proposed that in [2] but have since changed my mind. See
14d30cdfc04 (ref-filter: fix memory leak in `free_array_item()`,
2019-07-10), c514c62a4fd (checkout: fix leak of non-existent branch
names, 2020-08-14) and other log history hits for "free((char *)" for
prior art.

This includes the tests we had false-positive passes on before my
6798b08e848 (perl Git.pm: don't ignore signalled failure in
_cmd_close(), 2022-02-01), now they pass for real.

Since there are 66 tests matching t/t[0-9]*git-svn*.sh it's easier to
list those that don't pass than to touch most of those 66. So let's
introduce a "TEST_FAILS_SANITIZE_LEAK=true", which if set in the tests
won't cause lib-git-svn.sh to set "TEST_PASSES_SANITIZE_LEAK=true.

This change also marks all the tests that we removed
"TEST_FAILS_SANITIZE_LEAK=true" from in an earlier commit due to
removing the UNLEAK() from cmd_format_patch(), we can now assert that
its API use doesn't leak any "struct rev_info" memory.

This change also made commit "t5503-tagfollow.sh" pass on current
master, but that would regress when combined with
ps/fetch-atomic-fixup's de004e848a9 (t5503: simplify setup of test
which exercises failure of backfill, 2022-03-03) (through no fault of
that topic, that change started using "git clone" in the test, which
has an outstanding leak). Let's leave that test out for now to avoid
in-flight semantic conflicts.

1. https://lore.kernel.org/git/YUj%2FgFRh6pwrZalY@carlos-mbp.lan/
2. https://lore.kernel.org/git/87o88obkb1.fsf@evledraar.gmail.com/

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