src: remove outdated Neuter() call in node_buffer.cc

This call was introduced in 827ee49 to avoid a crash in a
later `Neuter()` call that has later been removed in ebbbc5a,
rendering the original call unnecessary.

Refs: nodejs#3624
Refs: nodejs#5204

src/node_buffer.cc

@@ -402,11 +402,6 @@ MaybeLocal<Object> New(Environment* env,
   }
 
   Local<ArrayBuffer> ab = ArrayBuffer::New(env->isolate(), data, length);
-  // `Neuter()`ing is required here to prevent materialization of the backing
-  // store in v8. `nullptr` buffers are not writable, so this is semantically
-  // correct.
-  if (data == nullptr)
-    ab->Neuter();
   MaybeLocal<Uint8Array> ui = Buffer::New(env, ab, 0, length);
 
   CallbackInfo::New(env->isolate(), ab, callback, data, hint);