submodule--helper: fix a leak in "clone_submodule"

Fix a memory leak of the "clone_data_path" variable that we copy or
derive from the "struct module_clone_data" in clone_submodule(). This
code was refactored in preceding commits, but the leak has been with
us since f8eaa0ba98 (submodule--helper, module_clone: always operate
on absolute paths, 2016-03-31).

For the "else" case we don't need to xstrdup() the "clone_data->path",
and we don't need to free our own "clone_data_path". We can therefore
assign the "clone_data->path" to our own "clone_data_path" right away,
and only override it (and remember to free it!) if we need to
xstrfmt() a replacement.

In the case of the module_clone() caller it's from "argv", and doesn't
need to be free'd, and in the case of the add_submodule() caller we
get a pointer to "sm_path", which doesn't need to be directly free'd
either.

Fixing this leak makes several tests pass, so let's mark them as
passing with TEST_PASSES_SANITIZE_LEAK=true.

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

t/t1500-rev-parse.sh

@@ -4,6 +4,7 @@ test_description='test git rev-parse'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_one () {

t/t6008-rev-list-submodule.sh

@@ -8,6 +8,7 @@ test_description='git rev-list involving submodules that this repo has'
 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/t7414-submodule-mistakes.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='handling of common mistakes people may make with submodules'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'create embedded repository' '

t/t7506-status-submodule.sh

@@ -2,6 +2,7 @@
 
 test_description='git status for submodule'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_create_repo_with_commit () {

t/t7507-commit-verbose.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='verbose commit template'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 write_script "check-for-diff" <<\EOF &&