gh-120385: Fix reference leak in symtable (#120386)

Decref 'new_ste' if symtable_visit_annotations() fails.

Author: Eclips4

Python/symtable.c

@@ -2027,8 +2027,10 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
         }
 
         if (!symtable_visit_annotations(st, s, s->v.AsyncFunctionDef.args,
-                                        s->v.AsyncFunctionDef.returns, new_ste))
+                                        s->v.AsyncFunctionDef.returns, new_ste)) {
+            Py_DECREF(new_ste);
             VISIT_QUIT(st, 0);
+        }
         if (!symtable_enter_existing_block(st, new_ste)) {
             Py_DECREF(new_ste);
             VISIT_QUIT(st, 0);