[typedarrays] Check detached buffer at start of typed array methods

test/mjsunit/es6/typedarray-copywithin.js

 // Copyright 2015 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: --allow-natives-syntax
 
 var typedArrayConstructors = [
   Uint8Array,
   Int8Array,
   Uint16Array,
@@ skipping 222 matching lines @@
     [Symbol.toPrimitive]() {
       assertUnreachable("Parameter should not be processed when " +
                         "array.[[ViewedArrayBuffer]] is neutered.");
       return 0;
     }
   };
 
   var array = new constructor([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
   %ArrayBufferNeuter(array.buffer);
 
-  // TODO(caitp): this should throw due to being invoked on a TypedArray with a
-  // detached buffer (per v8:4648).
-  array.copyWithin(tmp, tmp, tmp);
+  assertThrows(() => array.copyWithin(tmp, tmp, tmp), TypeError);
   assertEquals(0, array.length, "array.[[ViewedArrayBuffer]] is detached");
 });