Remove the unused wait-forever-in-install-worker.js

This file should be deleted in https://chromium-review.googlesource.com/560633,
because the WPT test register-wait-forever-in-install-worker.https.html can
be passed now.

BUG=723037

Change-Id: I3f02b24127797b1dce999f0eb900866effbf127c
Reviewed-on: https://chromium-review.googlesource.com/646245Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Xiaofeng Zhang <xiaofeng.zhang@intel.com>
Cr-Commit-Position: refs/heads/master@{#499430}

third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/wait-forever-in-install-worker.js

-self.addEventListener('install', function(event) {
-    event.waitUntil(new Promise(function() {}));
-  });