Update <stdbool.h> test for C23.

Change-Id: Ic46ec91b20da4ddf32d139c5a54b6e9fbd40ca6b
diff --git a/tests/headers/posix/stdbool_h.c b/tests/headers/posix/stdbool_h.c
index f891a73..830c33c 100644
--- a/tests/headers/posix/stdbool_h.c
+++ b/tests/headers/posix/stdbool_h.c
@@ -31,10 +31,8 @@
 #include "header_checks.h"
 
 static void stdbool_h() {
-#if !defined(bool)
-#error bool
-#endif
-  MACRO_VALUE(true, 1);
-  MACRO_VALUE(false, 0);
+  TYPE(bool);
+  bool t = true;
+  bool f = false;
   MACRO_VALUE(__bool_true_false_are_defined, 1);
 }