There are only 2 language modes, not 3

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index ad58d84814e4a76026de383327d04153a3287bea..4796fcba242511f7d0c563d9aa481f59363bb784 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9158,7 +9158,7 @@ Handle<Map> Map::AsLanguageMode(Handle<Map> initial_map,
   Handle<Map> function_map(
       Map::cast(isolate->native_context()->get(map_index)));
 
-  STATIC_ASSERT(LANGUAGE_END == 3);
+  STATIC_ASSERT(LANGUAGE_END == 2);
   switch (language_mode) {
     case STRICT:
       transition_symbol = factory->strict_function_transition_symbol();
@@ -16618,7 +16618,7 @@ class StringSharedKey : public HashTableKey {
       // collection.
       Script* script(Script::cast(shared->script()));
       hash ^= String::cast(script->source())->Hash();
-      STATIC_ASSERT(LANGUAGE_END == 3);
+      STATIC_ASSERT(LANGUAGE_END == 2);
       if (is_strict(language_mode)) hash ^= 0x8000;
       hash += scope_position;
     }