[es6] Remove harmony-classes flag

src/scanner.h

Index: src/scanner.h
diff --git a/src/scanner.h b/src/scanner.h
index f387d84133f984ff5183b6b802d65cf5cb3293bb..5559b8424c389d763a4860656499ee0fb8ca4963 100644
--- a/src/scanner.h
+++ b/src/scanner.h
@@ -483,12 +483,7 @@ class Scanner {
   void SetHarmonyModules(bool modules) {
     harmony_modules_ = modules;
   }
-  bool HarmonyClasses() const {
-    return harmony_classes_;
-  }
-  void SetHarmonyClasses(bool classes) {
-    harmony_classes_ = classes;
-  }
+
   bool HarmonyUnicode() const { return harmony_unicode_; }
   void SetHarmonyUnicode(bool unicode) { harmony_unicode_ = unicode; }
 
@@ -803,8 +798,6 @@ class Scanner {
   bool has_multiline_comment_before_next_;
   // Whether we scan 'module', 'import', 'export' as keywords.
   bool harmony_modules_;
-  // Whether we scan 'class', 'extends', 'static' and 'super' as keywords.
-  bool harmony_classes_;
   // Whether we allow \u{xxxxx}.
   bool harmony_unicode_;
 };