check setting immortal in the free-threading build

Objects/longobject.c

@@ -3653,7 +3653,10 @@ long_dealloc(PyObject *self)
 {
     assert(self);
     if (_PyLong_IsCompact((PyLongObject *)self)) {
-        if (compact_int_is_small(self)) {
+
+        // test what happens if we do hit the "never should get called": we should expect memory leaks, but no crashes
+        int dotest = 1;
+        if (compact_int_is_small(self) || dotest) {
             /* This should never get called, but we also don't want to SEGV if
              * we accidentally decref small Ints out of existence. Instead,
              * since small Ints are immortal, re-set the reference count.