Make new Harmony constructors subclassing-friendly

src/arraybuffer.js

Index: src/arraybuffer.js
diff --git a/src/arraybuffer.js b/src/arraybuffer.js
index 4a4f570146568464dfe8938502e9a827be60c6cd..b3229a54654773efbf3d25ae14c90358ee954f11 100644
--- a/src/arraybuffer.js
+++ b/src/arraybuffer.js
@@ -32,12 +32,8 @@ var $ArrayBuffer = global.ArrayBuffer;
 // -------------------------------------------------------------------
 
 function ArrayBufferConstructor(length) { // length = 1
-  if (%_IsConstructCall()) {
-    var byteLength = ToPositiveInteger(length, 'invalid_array_buffer_length');
-    %ArrayBufferInitialize(this, byteLength);
-  } else {
-    throw MakeTypeError('constructor_not_function', ["ArrayBuffer"]);
-  }
+  var byteLength = ToPositiveInteger(length, 'invalid_array_buffer_length');
+  %ArrayBufferInitialize(this, byteLength);
 }
 
 function ArrayBufferGetByteLength() {