Node form layout bug when toolbar collapsed

Testing the patch on #2307533: Insufficient space at page bottom has turned up a bug where the node form container loses its clearfix while elements are still floated, causing the form submit buttons to sit too close to the bottom of the screen.

The problem reveals itself for me in Chrome browser on mac, on the node edit page at screen width <= 975px, with the admin menu "Manage" tab (sidebar) collapsed.

The problem boils down to an interaction between the Seven theme stylesheet, and the Node module stylesheet that has to manually be kept in sync which is challenging:

Problematic code:

<div class="layout-node-form clearfix">

//core/themes/seven/css/style.css
/**
 * Widescreen
 *
 * Both of the following media queries must *exactly* match what is in
 * node.module.css. This is rather crazy.
 *
 * @todo Figure out how to reduce media query duplication across files
 *       and modules. Layout styles only allowed in themes?
 */
@media
  screen and (max-width: 1020px),
  (orientation: landscape) and (max-device-height: 1020px) {

  //  ... other code here ...

  .toolbar-vertical .layout-node-form:after {
    display: none;
  }
}

The above code essentially unsets the "clearfix" defined on the div=

// Core/modules/node/css/node.module.css
/**
 * The vertical toolbar mode gets triggered for narrow screens, which throws off
 * the intent of media queries written for the viewport width. When the vertical
 * toolbar is on, we need to suppress layout for the original media width + the
 * toolbar width (240px). In this case, 240px + 780px.
 */
@media
  screen and (max-width: 1020px) {

  .toolbar-vertical.toolbar-tray-open .layout-region-node-main,
  .toolbar-vertical.toolbar-tray-open .layout-region-node-footer,
  .toolbar-vertical.toolbar-tray-open .layout-region-node-secondary {
    float: none;
    width: auto;
    padding-right: 0;
  }
}

The media queries match, but the css rules do not. Because the toolbar is collapsed the node modules css doen't unfloat the items, but the seven stylesheet still does unset the clearfix.