t9141: use test_path_is_missing()

The test_must_fail() function should only be used for git commands since
we assume that external commands work sanely. Since, not only should
these directories not exist, but there shouldn't exist _any_ filesystem
entity in these paths, replace `test_must_fail test -d` with
`test_path_is_missing`.

Signed-off-by: Denton Liu <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Denton-L

t/t9141-git-svn-multiple-branches.sh

@@ -90,10 +90,10 @@ test_expect_success 'Multiple branch or tag paths require -d' '
 	) &&
 	( cd svn_project &&
 		svn_cmd up &&
-		test_must_fail test -d b_one/Nope &&
-		test_must_fail test -d b_two/Nope &&
-		test_must_fail test -d tags_A/Tagless &&
-		test_must_fail test -d tags_B/Tagless
+		test_path_is_missing b_one/Nope &&
+		test_path_is_missing b_two/Nope &&
+		test_path_is_missing tags_A/Tagless &&
+		test_path_is_missing tags_B/Tagless
 	)
 '