Fix infinite checkout loader when some script wasn't loaded correctly because of network error

[vovayatsyuk]

Description

Infinite checkout loader may appear when some module makes a require call but the dependency wasn't returned (Network error).

The patch changes how Magento treats isPending modules. If all dependencies are errored - treat it as loaded.

Manual testing scenarios

1. Open Magento/Checkout/view/frontend/web/js/model/quote.js
2. Insert the following code:

require([
    'jquery',
    'https://some-site/tracking/api/js'
], function ($) {}, function () {});

right after

define([
    'ko',
    'underscore'
], function (ko, _) {
    'use strict';

    // add code here

3. Navigate to checkout.
4. You can't purchase the product because the page is blocked by loader.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

@vovayatsyuk thank you for contributing. Please accept Community Contributors team invitation here to gain extended permissions for this repository.

[magento-engcom-team]

Hi @vovayatsyuk. Thank you for your contribution.
Changes from your Pull Request will be available with the upcoming 2.2.5 release.

[eTonki]

it still does not load checkout even in version 2.2.5
I see the problem in chrome but not in firefox
I understood that the blockage is due to this extension of the antivirus:
https://chrome.google.com/webstore/detail/avira-browser-safety/flliilndjeohchalpbbcdekjklbdgfkk?hl=en

[cbartak-rivet]

We are also seeing this issue in 2.2.5, with customers who have ad blockers installed (notably Ad Block Plus).

[DrewML]

@cbartak-rivet I'd recommend opening a new issue with a stack trace if you can replicate the issue.