Remove regress-crbug-518748. It's too hard to make this non-flaky

BUG=chromium:518748
R=mstarzinger@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1297403002 .

Cr-Commit-Position: refs/heads/master@{#30257}

test/mjsunit/mjsunit.status

@@ -256,9 +256,6 @@
   # BUG(v8:4378).
   'regress/regress-crbug-501711': [PASS, ['isolates', SKIP]],
   'regress/regress-4279': [PASS, ['isolates', SKIP]],
-
-  # BUG(chromium:518748)
-  'regress/regress-crbug-518748': [SKIP],
 }],  # ALWAYS
 
 ['novfp3 == True', {

test/mjsunit/regress/regress-crbug-518748.js

-// Copyright 2015 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.
-
-if (this.Worker) {
-  var workersToCreate = 1000;
-  var workers = [];
-  assertThrows(function() {
-    for (var i = 0; i < workersToCreate; i++) {
-      workers.push(new Worker(''));
-    }
-  });
-  print('#workers: ', workers.length);
-}