[debugger] Further stepping support in test wrapper

test/debugger/debug/debug-evaluate-shadowed-context-2.js

 // Copyright 2016 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.
 
-// Flags: --expose-debug-as debug --no-analyze-environment-liveness
 
 // Test that debug-evaluate correctly collects free outer variables
 // and does not get confused by variables in nested scopes.
 
 Debug = debug.Debug
 
 var exception = null;
 function listener(event, exec_state, event_data, data) {
   if (event != Debug.DebugEvent.Break) return;
   try {
@@ skipping 16 matching lines @@
         let x = 3;
         (() => x);
       }
       debugger;
     })();
   })();
 })();
 
 Debug.setListener(null);
 assertNull(exception);