Add menu option to “New Post” menu in admin bar

Use new-content :

function make_parent_node($wp_admin_bar) {
    $args = array(
        'id' => 'test1234', // id of the existing child node (New > Post)
        'title' => 'test', // alter the title of existing node
        'parent' => 'new-content', // set parent to false to make it a top level (parent) node
        'href' => admin_url('admin.php?page=enter_timesheet')
    );
    $wp_admin_bar->add_node($args);
}

it will show at the bottom:

you can see the ID of the parent node in the HTML if you dont want to dig in the core files:

they will be like wp-admin-bar-{ID-name}