[debugger] Hide scopes that originate from desugaring.

test/mjsunit/es6/regress/regress-468661.js

Index: test/mjsunit/es6/regress/regress-468661.js
diff --git a/test/mjsunit/es6/regress/regress-468661.js b/test/mjsunit/es6/regress/regress-468661.js
index 4a4235093033eec5717414b61f2bff889b12a042..d2c01ea62285908ea1f20e7967a59898fab36c78 100644
--- a/test/mjsunit/es6/regress/regress-468661.js
+++ b/test/mjsunit/es6/regress/regress-468661.js
@@ -9,7 +9,8 @@ var exception = null;
 var break_count = 0;
 
 var expected_values =
-  [ReferenceError, undefined, 0, 0, 0, 0, 1, ReferenceError, ReferenceError];
+  [ReferenceError, ReferenceError, 0, 0, 0, 0, 1,
+   ReferenceError, ReferenceError];
 
 function listener(event, exec_state, event_data, data) {
   try {
@@ -39,7 +40,6 @@ function listener(event, exec_state, event_data, data) {
         assertTrue(v instanceof ReferenceError);
       } else {
         assertSame(expected_values[break_count], v);
-
       }
       ++break_count;