Fix Label::draw skips drawing when batchNodes are more than one and h…

…ave empty quads. cocos2d/cocos2d-x#20528

cocos/2d/CCLabel.cpp

@@ -1773,7 +1773,7 @@ void Label::draw(Renderer *renderer, const Mat4 &transform, uint32_t flags)
             {
                 auto textureAtlas = batchNode->getTextureAtlas();
                 if (!textureAtlas->getTotalQuads())
-                    return;
+                    continue;
 
                 auto &batch = _batchCommands[i++];
                 auto &&commands = batch.getCommandArray();