leak tests: mark t5583-push-branches.sh as leak-free

When t5583-push-branches.sh was originally introduced via 425b4d7
(push: introduce '--branches' option, 2023-05-06), it was not leak-free.
In fact, the test did not even run correctly until 022fbb6 (t5583:
fix shebang line, 2023-05-12), but after applying that patch, we see a
failure at t5583.8:

    ==2529087==ERROR: LeakSanitizer: detected memory leaks

    Direct leak of 384 byte(s) in 1 object(s) allocated from:
        #0 0x7fb536330986 in __interceptor_realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98
        #1 0x55e07606cbf9 in xrealloc wrapper.c:140
        #2 0x55e075fb6cb3 in prio_queue_put prio-queue.c:42
        #3 0x55e075ec81cb in get_reachable_subset commit-reach.c:917
        #4 0x55e075fe9cce in add_missing_tags remote.c:1518
        #5 0x55e075fea1e4 in match_push_refs remote.c:1665
        git#6 0x55e076050a8e in transport_push transport.c:1378
        #7 0x55e075e2eb74 in push_with_options builtin/push.c:401
        git#8 0x55e075e2edb0 in do_push builtin/push.c:458
        git#9 0x55e075e2ff7a in cmd_push builtin/push.c:702
        git#10 0x55e075d8aaf0 in run_builtin git.c:452
        git#11 0x55e075d8af08 in handle_builtin git.c:706
        git#12 0x55e075d8b12c in run_argv git.c:770
        git#13 0x55e075d8b6a0 in cmd_main git.c:905
        git#14 0x55e075e81f07 in main common-main.c:60
        git#15 0x7fb5360ab6c9 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
        git#16 0x7fb5360ab784 in __libc_start_main_impl ../csu/libc-start.c:360
        git#17 0x55e075d88f40 in _start (git+0x1ff40) (BuildId: 38ad998b85a535e786129979443630d025ec2453)

    SUMMARY: LeakSanitizer: 384 byte(s) leaked in 1 allocation(s).

This leak was addressed independently via 68b5117 (commit-reach: fix
memory leak in get_reachable_subset(), 2023-06-03), which makes t5583
leak-free.

But t5583 was not in the tree when 68b5117 was written, and the two
only met after the latter was merged back in via 693bde4 (Merge
branch 'mh/commit-reach-get-reachable-plug-leak', 2023-06-20).

At that point, t5583 was leak-free. Let's mark it as such accordingly.

Signed-off-by: Taylor Blau <me@ttaylorr.com>

t/t5583-push-branches.sh

@@ -5,6 +5,7 @@ test_description='check the consisitency of behavior of --all and --branches'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 delete_refs() {