Test that TypedArray constructor throws when detaching buffer in length calculation

This test is only valid with the PR in https://github.com/tc39/ecma262/pull/852

test/built-ins/TypedArrays/buffer-arg-detached.js

@@ -7,7 +7,7 @@ info: >
   22.2.4.5 TypedArray ( buffer [ , byteOffset [ , length ] ] )
 
   ...
-  8. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
+  9. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
   ...
 includes: [testTypedArray.js, detachArrayBuffer.js]
 ---*/

test/built-ins/TypedArrays/byteoffset-arg-detachbuffer.js

@@ -7,7 +7,7 @@ info: >
   22.2.4.5 TypedArray ( buffer [ , byteOffset [ , length ] ] )
 
   ...
-  8. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
+  9. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
   ...
 includes: [testTypedArray.js, detachArrayBuffer.js]
 ---*/

test/built-ins/TypedArrays/length-arg-detachbuffer.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2017 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-typedarray-buffer-byteoffset-length
+description: If TypedArray() is passed a detached buffer, throw
+info: >
+  22.2.4.5 TypedArray ( buffer [ , byteOffset [ , length ] ] )
+
+  ...
+  9. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
+  ...
+includes: [testTypedArray.js, detachArrayBuffer.js]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  var offset = TA.BYTES_PER_ELEMENT;
+  var buffer = new ArrayBuffer(3 * offset);
+  var length = { valueOf() { $DETACHBUFFER(buffer); return 1; } };
+  assert.throws(TypeError, () => new TA(buffer, 0, length));
+});