Avoid using deprecated method waitForTimeout

[jcoyne]

Fixes #3947

[marlo-longley]

Thanks @jcoyne -- locally I got 4 failing tests with the suggestion to add testname-fn-timeout instead. For example:

● Window Sidebars › renders canvas navigation and updates canvas after clicking a navigation item

    thrown: "Exceeded timeout of 10000 ms for a hook.
    Add a timeout value to this test to increase the timeout, if this is a long-running test. See https://jestjs.io/docs/api#testname-fn-timeout."

      2 |
      3 | describe('Window Sidebars', () => {
    > 4 |   beforeAll(async () => {
        |   ^
      5 |     await page.goto('http://127.0.0.1:4488/__tests__/integration/mirador/blank.html');
      6 |
      7 |     await expect(page).toClick('#addBtn');

      at beforeAll (__tests__/integration/mirador/window_sidebar.test.js:4:3)
      at Object.describe (__tests__/integration/mirador/window_sidebar.test.js:3:1)

Is there a reason to remove the wait time rather than replace it with the newer methods/syntax?

[jcoyne]

@marlo-longley I don't understand what you mean by the newer syntax. The method waitForTimeout is removed puppeteer/puppeteer#11780

[cbeer]

I'm not seeing any local failures from this change (although there's something funny about one of the plugin tests, unrelated to this.). I don't think any of the waitForTimeout calls are anything but trying to address flappy tests, but maybe the ecosystem has improved...