[debugger] Further stepping support in test wrapper

test/mjsunit/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 {
-    assertThrows(() => exec_state.frame(0).evaluate("x").value());
-  } catch (e) {
-    exception = e;
-    print(e + e.stack);
-  }
-}
-
-Debug.setListener(listener);
-
-(function() {
-  var x = 1;     // context allocate x
-  (() => x);
-  (function() {
-    var x = 2;   // stack allocate shadowing x
-    (function() {
-      {          // context allocate x in a nested scope
-        let x = 3;
-        (() => x);
-      }
-      debugger;
-    })();
-  })();
-})();
-
-Debug.setListener(null);
-assertNull(exception);