Revert of [es6] Introduce spec compliant IsConstructor.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 2efd7ef6597a5e9cb174a9a2301eb6898a3ec28d..4aa0ea18b56950802b79c2c1c82f2a5091b28fa6 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -189,12 +189,6 @@
 
 bool Object::IsCallable() const {
   return Object::IsHeapObject() && HeapObject::cast(this)->map()->is_callable();
-}
-
-
-bool Object::IsConstructor() const {
-  return Object::IsHeapObject() &&
-         HeapObject::cast(this)->map()->is_constructor();
 }
 
 
@@ -4538,17 +4532,13 @@
 }
 
 
-void Map::set_is_constructor(bool value) {
-  if (value) {
-    set_bit_field(bit_field() | (1 << kIsConstructor));
-  } else {
-    set_bit_field(bit_field() & ~(1 << kIsConstructor));
-  }
-}
-
-
-bool Map::is_constructor() const {
-  return ((1 << kIsConstructor) & bit_field()) != 0;
+void Map::set_function_with_prototype(bool value) {
+  set_bit_field(FunctionWithPrototype::update(bit_field(), value));
+}
+
+
+bool Map::function_with_prototype() {
+  return FunctionWithPrototype::decode(bit_field());
 }
 
 
@@ -4805,7 +4795,6 @@
   return instance_type() >= FIRST_JS_OBJECT_TYPE;
 }
 bool Map::IsJSArrayMap() { return instance_type() == JS_ARRAY_TYPE; }
-bool Map::IsJSFunctionMap() { return instance_type() == JS_FUNCTION_TYPE; }
 bool Map::IsStringMap() { return instance_type() < FIRST_NONSTRING_TYPE; }
 bool Map::IsJSProxyMap() {
   InstanceType type = instance_type();
@@ -6264,6 +6253,11 @@
     return prototype;
   }
   return instance_prototype();
+}
+
+
+bool JSFunction::should_have_prototype() {
+  return map()->function_with_prototype();
 }