[DevTools] Do not collapse toolbars

chrome/browser/resources/inspect/inspect.css

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 * {
   box-sizing: border-box;
 }
 
 body {
   color: rgb(48, 57, 66);
   font-size: 13px;
   margin: 0;
   min-width: 47em;
+  overflow: hidden;
 }
 
 .hidden {
     display: none !important;
 }
 
 img {
   flex-shrink: 0;
   height: 16px;
   padding-left: 2px;
@@ skipping 415 matching lines @@
 @media (min-width: 47em) {
   #container {
     max-height: 100vh;
   }
   #navigation,
   #content {
     max-height: 100vh;
     overflow: auto;
   }
 }