leak tests: mark a handful of tests as leak-free

In the topic merged via 5a4f838 (Merge branch
'ab/mark-leak-free-tests', 2021-10-25), a handful of tests in the suite
were marked as leak-free.

As far as I can tell, each patch from that series ran tests from a
handful of subject areas, such as "some ls-files tests", or "all trace2
tests". This left some gaps in which tests had and hadn't been audited
to be leak-free.

This patch closes those gaps by exporting TEST_PASSES_SANITIZE_LEAK=true
before sourcing t/test-lib.sh on most remaining leak-free tests. This
list was compiled by doing:

    $ make SANITIZE=leak
    $ make \
        GIT_TEST_PASSING_SANITIZE_LEAK=check \
        GIT_TEST_SANITIZE_LEAK_LOG=true \
        GIT_TEST_OPTS=-vi test

and looking through the list of failing tests in the output.

There are a couple of other tests which are similarly leak-free, but not
included in the list of tests touched by this patch. The remaining tests
will be addressed in the subsequent two patches.

Signed-off-by: Taylor Blau <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ttaylorr

t/t5571-pre-push-hook.sh

@@ -4,6 +4,7 @@ test_description='check pre-push hooks'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '

t/t7516-commit-races.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='git commit races'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'race to create orphan commit' '