Factor out core of Array.forEach and .every, for use in TypedArrays

test/mjsunit/harmony/typedarrays-foreach.js

 // Copyright 2014 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.
 
 // Flags: --harmony-arrays --allow-natives-syntax
 
 var typedArrayConstructors = [
   Uint8Array,
   Int8Array,
   Uint16Array,
@@ skipping 67 matching lines @@
       array[index] = n + 1;
       count++;
     });
   } catch (e) {
   }
   assertEquals(1, count);
   assertEquals(43, a[0]);
   assertEquals(42, a[1]);
 
   // Neutering the buffer backing the typed array mid-way should
-  // still make .forEach() finish, and the array should keep being
-  // empty after neutering it.
+  // still make .forEach() finish, but exiting early due to the missing
+  // elements, and the array should keep being empty after detaching it.
+  // TODO(dehrenberg): According to the ES6 spec, accessing or testing
+  // for members on a detached TypedArray should throw, so really this
+  // should throw in the third iteration. However, this behavior matches
+  // the Khronos spec.
+  a = new constructor(3);
   count = 0;
   a.forEach(function (n, index, array) {
     if (count > 0) %ArrayBufferNeuter(array.buffer);
     array[index] = n + 1;
     count++;
   });
   assertEquals(2, count);
   CheckTypedArrayIsNeutered(a);
   assertEquals(undefined, a[0]);
 
@@ skipping 31 matching lines @@
     count = 0;
     a = new typedArrayConstructors[i](4);
     constructor.prototype.forEach.call(a, function (x) { count++ });
     assertEquals(a.length, count);
   }
 }
 
 for (i = 0; i < typedArrayConstructors.length; i++) {
   TestTypedArrayForEach(typedArrayConstructors[i]);
 }