fix Tee iternext index adjustment

Author: qunaibit

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/itertools/TeeBuiltins.java

@@ -166,8 +166,10 @@ static Object nextNext(VirtualFrame frame, PTee self,
                         @Bind PythonLanguage language,
                         @Shared @Cached PRaiseNode raiseNode) {
             self.setDataObj(self.getDataobj().jumplink(language));
+            self.setIndex(0);
+            Object ret = self.getDataobj().getItem(frame, inliningTarget, 0, nextNode, raiseNode);
             self.setIndex(1);
-            return self.getDataobj().getItem(frame, inliningTarget, 0, nextNode, raiseNode);
+            return ret;
         }
     }