Revert of Remove Scope::scope_uses_this_ flag

src/preparser.h

Index: src/preparser.h
diff --git a/src/preparser.h b/src/preparser.h
index 543f82ee56a281dfc5984a7aa9a9be91319cf659..8184bd8d5f5af2bc93a872c80c71ab3b7cce8001 100644
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -2215,6 +2215,7 @@
           break;
         }
       }
+      scope_->RecordThisUsage();
       result = this->ThisExpression(scope_, factory(), beg_pos);
       break;
     }
@@ -3240,6 +3241,7 @@
   Consume(Token::THIS);
   int pos = position();
   function_state_->set_this_location(scanner()->location());
+  scope_->RecordThisUsage();
   ExpressionT this_expr = this->ThisExpression(scope_, factory(), pos);
 
   ExpressionT left = this->EmptyExpression();