Add missing test for SharedArrayBuffer.prototype

test/built-ins/SharedArrayBuffer/prototype/prop-desc.js

@@ -0,0 +1,16 @@
+// Copyright (C) 2021 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-sharedarraybuffer.prototype
+description: Property descriptor of the 'prototype' property
+info: |
+  This property has the attributes { [[Writable]]: false, [[Enumerable]]:
+  false, [[Configurable]]: false }.
+includes: [propertyHelper.js]
+---*/
+
+verifyProperty(SharedArrayBuffer, 'prototype', {
+    enumerable: false,
+    writable: false,
+    configurable: false
+});