[DevTools] Move inspector-protocol/accessibility tests to new harness

third_party/WebKit/LayoutTests/inspector-protocol/accessibility/accessibility-modal-expected.txt

-Open Dialog
+
 {
   "nodeId": "<string>",
   "ignored": false,
   "role": {
     "type": "role",
     "value": "dialog"
   },
   "name": {
     "type": "computedString",
     "value": "",
@@ skipping 210 matching lines @@
       "name": "modal",
       "value": {
         "type": "boolean",
         "value": false
       }
     }
   ],
   "domNode": "dialog"
 }