buffer: clean up usage of __proto__

Prefer using Object.setPrototypeOf() instead.

PR-URL: #3080
Reviewed-By: Ben Noordhuis <[email protected]>

Author: trevnorris

lib/buffer.js

@@ -58,8 +58,8 @@ function Buffer(arg) {
   return fromObject(arg);
 }
 
-Buffer.prototype.__proto__ = Uint8Array.prototype;
-Buffer.__proto__ = Uint8Array;
+Object.setPrototypeOf(Buffer.prototype, Uint8Array.prototype);
+Object.setPrototypeOf(Buffer, Uint8Array);
 
 
 function SlowBuffer(length) {
@@ -72,8 +72,8 @@ function SlowBuffer(length) {
   return ui8;
 }
 
-SlowBuffer.prototype.__proto__ = Buffer.prototype;
-SlowBuffer.__proto__ = Buffer;
+Object.setPrototypeOf(SlowBuffer.prototype, Uint8Array.prototype);
+Object.setPrototypeOf(SlowBuffer, Uint8Array);
 
 
 function allocate(size) {