tests: plug a couple of leaks

tests-clar/diff/workdir.c

@@ -897,6 +897,7 @@ void test_diff_workdir__can_diff_empty_file(void)
 	/* baseline - make sure there are no outstanding diffs */
 
 	cl_git_pass(git_diff_tree_to_workdir(&diff, g_repo, tree, &opts));
+	git_tree_free(tree);
 	cl_assert_equal_i(2, (int)git_diff_num_deltas(diff));
 	git_diff_list_free(diff);
 

tests-clar/network/cred.c

@@ -23,5 +23,5 @@ void test_network_cred__stock_userpass_validates_that_method_is_allowed(void)
 
 	cl_git_fail(git_cred_userpass(&cred, NULL, 0, &payload));
 	cl_git_pass(git_cred_userpass(&cred, NULL, GIT_CREDTYPE_USERPASS_PLAINTEXT, &payload));
-	git__free(cred);
+	cred->free(cred);
 }