Revert of Fix async/await memory leak

test/mjsunit/harmony/async-await-throw-loop.js

-// Copyright 2016 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --harmony-async-await --allow-natives-syntax --max-old-space-size 3
-
-let out;
-
-async function thrower() { throw undefined; }
-
-async function throwLoop() {
-  for (let i = 0; i < 8000; i++) {
-    try { await thrower(); }
-    catch (e) {}
-  }
-  out = 2;
-}
-
-throwLoop();
-
-%RunMicrotasks();
-
-assertEquals(2, out);