[es6] Introduce spec compliant IsConstructor.

src/contexts.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_CONTEXTS_H_
 #define V8_CONTEXTS_H_
 
 #include "src/heap/heap.h"
 #include "src/objects.h"
 
@@ skipping 495 matching lines @@
     return kHeaderSize + index * kPointerSize - kHeapObjectTag;
   }
 
   static int FunctionMapIndex(LanguageMode language_mode, FunctionKind kind) {
     if (IsGeneratorFunction(kind)) {
       return is_strong(language_mode) ? STRONG_GENERATOR_FUNCTION_MAP_INDEX :
              is_strict(language_mode) ? STRICT_GENERATOR_FUNCTION_MAP_INDEX
                                       : SLOPPY_GENERATOR_FUNCTION_MAP_INDEX;
     }
 
-    if (IsConstructor(kind)) {
+    if (IsClassConstructor(kind)) {
       // Use strict function map (no own "caller" / "arguments")
       return is_strong(language_mode) ? STRONG_CONSTRUCTOR_MAP_INDEX
                                       : STRICT_FUNCTION_MAP_INDEX;
     }
 
     if (IsArrowFunction(kind) || IsConciseMethod(kind) ||
         IsAccessorFunction(kind)) {
       return is_strong(language_mode)
                  ? STRONG_FUNCTION_MAP_INDEX
                  : STRICT_FUNCTION_WITHOUT_PROTOTYPE_MAP_INDEX;
@@ skipping 23 matching lines @@
   static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object);
 #endif
 
   STATIC_ASSERT(kHeaderSize == Internals::kContextHeaderSize);
   STATIC_ASSERT(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONTEXTS_H_