[inspector] Refactor protocol-test.js

test/inspector/debugger/collect-old-async-call-chains.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.
 
-InspectorTest.log('Checks that we drop old async call chains.');
+let {session, contextGroup, Protocol} = InspectorTest.start('Checks that we drop old async call chains.');
 
 Protocol.Debugger.enable();
 Protocol.Runtime.enable();
 InspectorTest.runAsyncTestSuite([
   async function testInfrastructure() {
     Protocol.Debugger.setAsyncCallStackDepth({maxDepth: 128});
     await setMaxAsyncTaskStacks(1024);
     runWithAsyncChainPromise(1, 'console.trace(42)');
     dumpAsyncChainLength(await Protocol.Runtime.onceConsoleAPICalled());
 
@@ skipping 146 matching lines @@
     stackTrace = stackTrace.parent;
   }
   InspectorTest.log(`actual async chain len: ${asyncChainCount}\n`);
 }
 
 async function setMaxAsyncTaskStacks(max) {
   let expression = `inspector.setMaxAsyncTaskStacks(${max})`;
   InspectorTest.log(expression);
   await Protocol.Runtime.evaluate({expression});
 }