t: mark a bunch of tests as leak-free

t: mark a bunch of tests as leak-free

There are a bunch of tests which do not have any leaks:

  - t0411: Introduced via 5c5a4a1c05 (t0411: add tests for cloning from
    partial repo, 2024-01-28), passes since its inception.

  - t0610: Introduced via 57db2a094d (refs: introduce reftable backend,
    2024-02-07), passes since its inception.

  - t2405: Passes since 6741e917de (repository: avoid leaking
    `fsmonitor` data, 2024-04-12).

  - t7423: Introduced via b20c10fd9b (t7423: add tests for symlinked
    submodule directories, 2024-01-28), passes since e8d0608944
    (submodule: require the submodule path to contain directories only,
    2024-03-26). The fix is not obviously related, but probably works
    because we now die early in many code paths.

  - t9xxx: All of these are exercising CVS-related tooling and pass
    since at least Git v2.40. It's likely that these pass for a long
    time already, but nobody ever noticed because Git developers do not
    tend to have CVS on their machines.

Mark all of these tests as passing.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>