[inspector] Refactor inspector test

test/inspector/runtime/runtime-restore.js

 // Copyright 2017 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.v8
 
 InspectorTest.log('Checks that Runtime agent correctly restore its state.');
 
 InspectorTest.addScript(`
 var formatter = {
     header: function(x)
     {
@@ skipping 38 matching lines @@
       .then(() => Protocol.Runtime.evaluate({ expression: 'console.log(42);' }))
       .then(Protocol.Runtime.disable)
       .then(() => {
         Protocol.Runtime.onConsoleAPICalled(null);
         next();
       });
   },
 
   function testSetCustomObjectFormatterEnabled(next) {
     Protocol.Runtime.onConsoleAPICalled(InspectorTest.logMessage);
-    // cleanup console message storage
-    reconnect();
-    Protocol.Runtime.enable()
+    Protocol.Runtime.discardConsoleEntries()
+      .then(reconnect)
+      .then(() => Protocol.Runtime.enable())
       .then(() => Protocol.Runtime.setCustomObjectFormatterEnabled({ enabled: true }))
       .then(reconnect)
       .then(() => Protocol.Runtime.evaluate({ expression: 'console.log({ name: 42 })'}))
       .then(InspectorTest.logMessage)
       .then(Protocol.Runtime.disable)
       .then(() => {
         Protocol.Runtime.onConsoleAPICalled(null);
         next();
       });
   },
 ]);
 
 function reconnect() {
   InspectorTest.logMessage('will reconnect..');
-  utils.reconnect();
+  InspectorTest.session.reconnect();
 }