buffer: fix performance regression

V8 5.4 changed the way that the default constructor of derived classes
is called. It introduced a significant performance regression in the
buffer module for the creation of pooled buffers. This commit forces the
definition back to how it was implicitly before.

Ref: https://bugs.chromium.org/p/v8/issues/detail?id=4890

PR-URL: #8754
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>

lib/buffer.js

@@ -6,7 +6,11 @@ const { isArrayBuffer, isSharedArrayBuffer } = process.binding('util');
 const bindingObj = {};
 const internalUtil = require('internal/util');
 
-class FastBuffer extends Uint8Array {}
+class FastBuffer extends Uint8Array {
+  constructor(arg1, arg2, arg3) {
+    super(arg1, arg2, arg3);
+  }
+}
 
 FastBuffer.prototype.constructor = Buffer;
 Buffer.prototype = FastBuffer.prototype;