[BUG] Site doesn't load on Windows webkit

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Context:

• Playwright Version: 1.20.1
• Operating System: Windows 10
• Node.js version: 12.22
• Browser: Webkit
• Extra: [any specific details about your environment]

Code Snippet

Help us help you! Put down a short code snippet that illustrates your bug and
that we can run and debug locally. For example:

test('example test', async ({ page }) => {
  await page.goto(<MY_URL>); //Can share the url privately on slack 
  await.page.pause();
});

//config.js
{
  name: 'Desktop Safari',
  use: { browserName: 'webkit' },
},

Describe the bug
I have site that doesn't load properly on Windows-webkit. Only a chat button is loaded and login form doesn't render at all. Works fine on Mac webkit.

[pavelfeldman]

Folding into #12823