Make TypedArray.from and TypedArray.of writable and configurable

test/mjsunit/es6/typedarray-of.js

Index: test/mjsunit/es6/typedarray-of.js
diff --git a/test/mjsunit/es6/typedarray-of.js b/test/mjsunit/es6/typedarray-of.js
index a6df29a0ddc858205a1afd78a9074b7ca2128502..eaa7bde11b366581bf6fc4277ff1266386de9520 100644
--- a/test/mjsunit/es6/typedarray-of.js
+++ b/test/mjsunit/es6/typedarray-of.js
@@ -115,9 +115,9 @@ function TestTypedArrayOf(constructor) {
   // Check superficial features of %TypedArray%.of.
   var desc = Object.getOwnPropertyDescriptor(constructor.__proto__, "of");
 
-  assertEquals(desc.configurable, false);
+  assertEquals(desc.configurable, true);
   assertEquals(desc.enumerable, false);
-  assertEquals(desc.writable, false);
+  assertEquals(desc.writable, true);
   assertEquals(constructor.of.length, 0);
 
   // %TypedArray%.of is not a constructor.