Remove --harmony-scoping flag.

src/preparser.h

Index: src/preparser.h
diff --git a/src/preparser.h b/src/preparser.h
index 6e2a9de575bf3d8c4b086a82829e3fb094733495..7f873bd12f1b856537af06cf0891b7d413f08161 100644
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -100,7 +100,6 @@ class ParserBase : public Traits {
     return allow_harmony_arrow_functions_;
   }
   bool allow_harmony_modules() const { return scanner()->HarmonyModules(); }
-  bool allow_harmony_scoping() const { return scanner()->HarmonyScoping(); }
   bool allow_harmony_numeric_literals() const {
     return scanner()->HarmonyNumericLiterals();
   }
@@ -130,9 +129,6 @@ class ParserBase : public Traits {
   void set_allow_harmony_modules(bool allow) {
     scanner()->SetHarmonyModules(allow);
   }
-  void set_allow_harmony_scoping(bool allow) {
-    scanner()->SetHarmonyScoping(allow);
-  }
   void set_allow_harmony_numeric_literals(bool allow) {
     scanner()->SetHarmonyNumericLiterals(allow);
   }
@@ -2944,7 +2940,7 @@ ParserBase<Traits>::ParseArrowFunctionLiteral(int start_pos,
                               CHECK_OK);
     }
 
-    if (allow_harmony_scoping() && is_strict(language_mode()))
+    if (is_strict(language_mode()))
       this->CheckConflictingVarDeclarations(scope, CHECK_OK);
   }