[inspector] Refactor protocol-test.js

test/inspector/debugger/return-break-locations.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('Return break locations within function');
+let {session, contextGroup, Protocol} = InspectorTest.start('Return break locations within function');
 
-InspectorTest.addScript(`
+contextGroup.addScript(`
 function fib(x) {
   if (x < 0) return;
   if (x === 0) return 1;
   if (x === 1) return fib(0);
   return x > 2 ? fib(x - 1) + fib(x - 2) : fib(1) + fib(0);
 }
 `);
 
 InspectorTest.runAsyncTestSuite([
   async function testTailCall() {
     var scriptPromise = Protocol.Debugger.onceScriptParsed();
     Protocol.Debugger.enable();
     var scriptId = (await scriptPromise).params.scriptId;
     var locations = (await Protocol.Debugger.getPossibleBreakpoints({
       start: { lineNumber: 0, columnNumber: 0, scriptId }
     })).result.locations;
     InspectorTest.logMessage(locations.filter(location => location.type === 'return'));
   }
 ]);