[debugger] do not expose temporary variables introduced by the parser.

test/mjsunit/debug-scopes.js

Index: test/mjsunit/debug-scopes.js
diff --git a/test/mjsunit/debug-scopes.js b/test/mjsunit/debug-scopes.js
index 37a1ce5eaf27ca4d3109ea56736566428b6b7bb5..935de9cc98b08eb564eb22f73c37041a50f0e33c 100644
--- a/test/mjsunit/debug-scopes.js
+++ b/test/mjsunit/debug-scopes.js
@@ -183,10 +183,8 @@ function CheckScopeContent(content, number, exec_state) {
   if (!scope.scopeObject().property('this').isUndefined()) {
     scope_size--;
   }
-  // Skip property with empty name.
-  if (!scope.scopeObject().property('').isUndefined()) {
-    scope_size--;
-  }
+  // Temporary variables introduced by the parser have not been materialized.
+  assertTrue(scope.scopeObject().property('').isUndefined());
 
   if (count != scope_size) {
     print('Names found in scope:');