[inspector] Refactor protocol-test.js

test/inspector/debugger/wasm-stepping.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.
 
+let {session, contextGroup, Protocol} = InspectorTest.start('Tests stepping through wasm scripts');
+
 utils.load('test/mjsunit/wasm/wasm-constants.js');
 utils.load('test/mjsunit/wasm/wasm-module-builder.js');
 
 var builder = new WasmModuleBuilder();
 
 var func_a_idx =
     builder.addFunction('wasm_A', kSig_v_v).addBody([kExprNop, kExprNop]).index;
 
 // wasm_B calls wasm_A <param0> times.
 builder.addFunction('wasm_B', kSig_v_i)
@@ skipping 177 matching lines @@
     }
   }
 }
 
 function handlePaused(msg) {
   var loc = msg.params.callFrames[0].location;
   printPauseLocation(loc.scriptId, loc.lineNumber, loc.columnNumber);
   dumpScopeChainsOnPause(msg)
       .then(Protocol.Debugger[step_actions.shift() || 'resume']);
 }