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

test/mjsunit/es6/typedarray-copywithin.js

Index: test/mjsunit/es6/typedarray-copywithin.js
diff --git a/test/mjsunit/es6/typedarray-copywithin.js b/test/mjsunit/es6/typedarray-copywithin.js
index 1e63508393f4c1b63897c638ee1a0ac007da5bb0..c52a38625b03b707f95249874273e158068417d0 100644
--- a/test/mjsunit/es6/typedarray-copywithin.js
+++ b/test/mjsunit/es6/typedarray-copywithin.js
@@ -240,8 +240,6 @@ CheckEachTypedArray(function parametersNotCalledIfDetached(constructor) {
   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");
 });