test-tool {dump,scrap}-cache-tree: fix memory leaks

Fix memory leaks in two test-tools used by t0090-cache-tree.sh. As a
result we can mark the test as passing with SANITIZE=leak using
"TEST_PASSES_SANITIZE_LEAK=true".

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

t/helper/test-dump-cache-tree.c

@@ -59,11 +59,16 @@ int cmd__dump_cache_tree(int ac, const char **av)
 {
 	struct index_state istate;
 	struct cache_tree *another = cache_tree();
+	int ret;
+
 	setup_git_directory();
 	if (read_cache() < 0)
 		die("unable to read index file");
 	istate = the_index;
 	istate.cache_tree = another;
 	cache_tree_update(&istate, WRITE_TREE_DRY_RUN);
-	return dump_cache_tree(active_cache_tree, another, "");
+	ret = dump_cache_tree(active_cache_tree, another, "");
+	cache_tree_free(&another);
+
+	return ret;
 }

t/helper/test-scrap-cache-tree.c

@@ -12,6 +12,7 @@ int cmd__scrap_cache_tree(int ac, const char **av)
 	hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
 	if (read_cache() < 0)
 		die("unable to read index file");
+	cache_tree_free(&active_cache_tree);
 	active_cache_tree = NULL;
 	if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 		die("unable to write index file");

t/t0090-cache-tree.sh

@@ -5,6 +5,8 @@ test_description="Test whether cache-tree is properly updated
 Tests whether various commands properly update and/or rewrite the
 cache-tree extension.
 "
+
+TEST_PASSES_SANITIZE_LEAK=true
  . ./test-lib.sh
 
 cmp_cache_tree () {