gh-157892: Fix error check on _Py_hashtable_set() in intern_static() (#157898)

_Py_hashtable_set() returns -1 on failure, so the "< -1" check could never be true and the Py_FatalError() call was unreachable.

Author: rishiraj38

Objects/unicodeobject.c

@@ -14588,7 +14588,7 @@ intern_static(PyInterpreterState *interp, PyObject *s /* stolen */)
         return Py_NewRef(r);
     }
 
-    if (_Py_hashtable_set(INTERNED_STRINGS, s, s) < -1) {
+    if (_Py_hashtable_set(INTERNED_STRINGS, s, s) < 0) {
         Py_FatalError("failed to intern static string");
     }