[inspector] Refactor protocol-test.js

test/inspector/debugger/stepping-tail-call.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 stepping over tail calls.');
+let {session, contextGroup, Protocol} = InspectorTest.start('Checks stepping over tail calls.');
 
-InspectorTest.setupScriptMap();
+session.setupScriptMap();
 InspectorTest.logProtocolCommandCalls('Debugger.pause');
 InspectorTest.logProtocolCommandCalls('Debugger.stepInto');
 InspectorTest.logProtocolCommandCalls('Debugger.stepOver');
 InspectorTest.logProtocolCommandCalls('Debugger.stepOut');
 InspectorTest.logProtocolCommandCalls('Debugger.resume');
 
 let source = `
 function f(x) {
   if (x == 2) debugger;
   if (x-- > 0) return f(x);
@@ skipping 51 matching lines @@
     await logPauseLocation(await Protocol.Debugger.oncePaused());
     Protocol.Debugger.stepOut();
     await logPauseLocation(await Protocol.Debugger.oncePaused());
     Protocol.Debugger.stepOut();
     await logPauseLocation(await Protocol.Debugger.oncePaused());
     await Protocol.Debugger.resume();
   }
 ]);
 
 function logPauseLocation(message) {
-  InspectorTest.logCallFrames(message.params.callFrames);
-  return InspectorTest.logSourceLocation(message.params.callFrames[0].location);
+  session.logCallFrames(message.params.callFrames);
+  return session.logSourceLocation(message.params.callFrames[0].location);
 }