pythongh-118849: Fix "code will never be executed" warning in `dictob…

…ject.c` (pythonGH-118850)

(cherry picked from commit 82abe75)

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>

Objects/dictobject.c

@@ -5396,6 +5396,7 @@ static int
 dictiter_iternext_threadsafe(PyDictObject *d, PyObject *self,
                              PyObject **out_key, PyObject **out_value)
 {
+    int res;
     dictiterobject *di = (dictiterobject *)self;
     Py_ssize_t i;
     PyDictKeysObject *k;
@@ -5491,7 +5492,6 @@ dictiter_iternext_threadsafe(PyDictObject *d, PyObject *self,
     Py_DECREF(d);
     return -1;
 
-    int res;
 try_locked:
     Py_BEGIN_CRITICAL_SECTION(d);
     res = dictiter_iternextitem_lock_held(d, self, out_key, out_value);