[DevTools] New harness for inspector-protocol layout tests

third_party/WebKit/LayoutTests/inspector-protocol/accessibility/accessibility-nameSources-buttons-expected.txt

+
 {
   "nodeId": "<string>",
   "ignored": false,
   "role": {
     "type": "role",
     "value": "button"
   },
   "name": {
     "type": "computedString",
     "value": "",
@@ skipping 539 matching lines @@
             "text": "label-for-button11",
             "nodeResult": "label"
           }
         ]
       }
     }
   ],
   "domNode": "button#button11"
 }