selftests/landlock: Fix error message

The global variable errno may not be set in test_execute().  Do not use
it in related error message.

Cc: Günther Noack <gnoack@google.com>
Fixes: e1199815b4 ("selftests/landlock: Add user space tests")
Link: https://lore.kernel.org/r/20250108154338.1129069-21-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

tools/testing/selftests/landlock/fs_test.c

@@ -2011,8 +2011,7 @@ static void test_execute(struct __test_metadata *const _metadata, const int err,
 	ASSERT_EQ(1, WIFEXITED(status));
 	ASSERT_EQ(err ? 2 : 0, WEXITSTATUS(status))
 	{
-		TH_LOG("Unexpected return code for \"%s\": %s", path,
-		       strerror(errno));
+		TH_LOG("Unexpected return code for \"%s\"", path);
 	};
 }