There are only 2 language modes, not 3

src/ic/ic-state.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_IC_STATE_H_
 #define V8_IC_STATE_H_
 
 #include "src/macro-assembler.h"
 
 namespace v8 {
@@ skipping 239 matching lines @@
   ExtraICState GetExtraICState() const { return state_; }
 
   LanguageMode language_mode() const {
     return LanguageModeState::decode(state_);
   }
 
   static LanguageMode GetLanguageMode(ExtraICState state) {
     return StoreICState(state).language_mode();
   }
 
-  class LanguageModeState : public BitField<LanguageMode, 1, 2> {};
-  STATIC_ASSERT(i::LANGUAGE_END == 3);
+  class LanguageModeState : public BitField<LanguageMode, 1, 1> {};
+  STATIC_ASSERT(i::LANGUAGE_END == 2);
 
   // For convenience, a statically declared encoding of strict mode extra
   // IC state.
   static const ExtraICState kStrictModeState = STRICT
                                                << LanguageModeState::kShift;
 
  private:
   const ExtraICState state_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_IC_STATE_H_