[debugger] tuned StepNext and StepOut at return position

test/debugger/debug/es6/debug-stepin-microtasks.js

 // Copyright 2014 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.
 
 
 Debug = debug.Debug
 var exception = null;
 var break_count = 0;
-const expected_breaks = 9;
+const expected_breaks = 10;
 
 function listener(event, exec_state, event_data, data) {
   try {
     if (event == Debug.DebugEvent.Break) {
       assertTrue(exec_state.frameCount() != 0, "FAIL: Empty stack trace");
       var source = exec_state.frame(0).sourceLineText();
       print("paused at: " + source);
       assertTrue(source.indexOf("// Break " + break_count + ".") > 0,
                  "Unexpected pause at: " + source + "\n" +
                  "Expected: // Break " + break_count + ".");
@@ skipping 38 matching lines @@
   return break_count; // Break 4.
 } // Break 5.
 
 function promise4() {
   finalize(); // Break 6. StepOver.
   return 0; // Break 7.
 } // Break 8. StepOut.
 
 function finalize() {
   Promise.resolve().then(function() {
-    if (expected_breaks !== break_count) {
+    if (expected_breaks !== break_count) { // Break 9. StepOut.
       %AbortJS("FAIL: expected <" + expected_breaks + "> breaks instead of <" +
                break_count + ">");
     }
     if (exception !== null) {
       %AbortJS("FAIL: exception: " + exception);
     }
   });
 }