[debugger] Further stepping support in test wrapper

test/mjsunit/debug-stepin-construct-call.js

-// Copyright 2015 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
-
-var break_count = 0;
-var exception = null;
-
-function listener(event, exec_state, event_data, data) {
-  if (event != Debug.DebugEvent.Break) return;
-  try {
-    var source_line = exec_state.frame(0).sourceLineText();
-    print(source_line);
-    exec_state.prepareStep(Debug.StepAction.StepIn);
-    break_count++;
-  } catch (e) {
-    exception = e;
-  }
-}
-
-var Debug = debug.Debug;
-Debug.setListener(listener);
-
-
-function f() {
-  this.x = 1;
-}
-
-function g() {
-  new f();
-}
-
-Debug.setBreakPoint(g, 6, Debug.BreakPositionAlignment.BreakPosition);
-print(Debug.showBreakPoints(g, undefined,
-      Debug.BreakPositionAlignment.BreakPosition));
-
-g();
-Debug.setListener(null);
-
-assertEquals(6, break_count);
-assertNull(exception);