test: unflake TestPageClock

[yury-s]

Fixes the following error on the bots:

Error:    TestPageClock.shouldNotRunTimeBeforePopupOnPause:313 » Playwright Error {
  message='ReferenceError: time is not defined
    at eval (eval at evaluate (:234:30), <anonymous>:1:1)
    at eval (<anonymous>)
    at UtilityScript.evaluate (<anonymous>:234:30)
    at UtilityScript.<anonymous> (<anonymous>:1:44)
  name='Error
  stack='Error: ReferenceError: time is not defined
    at eval (eval at evaluate (:234:30), <anonymous>:1:1)
    at eval (<anonymous>)
    at UtilityScript.evaluate (<anonymous>:234:30)
    at UtilityScript.<anonymous> (<anonymous>:1:44)
    at CRExecutionContext.evaluateWithArguments (/tmp/playwright-java-947970650740572645/package/lib/server/chromium/crExecutionContext.js:79:33)
    at async LongStandingScope._race (/tmp/playwright-java-947970650740572645/package/lib/utils/manualPromise.js:96:14)
    at async Object.evaluateExpression (/tmp/playwright-java-947970650740572645/package/lib/server/javascript.js:229:12)
    at async Frame.evaluateExpression (/tmp/playwright-java-947970650740572645/package/lib/server/frames.js:608:19)
    at async FrameDispatcher.evaluateExpression (/tmp/playwright-java-947970650740572645/package/lib/server/dispatchers/frameDispatcher.js:92:55)
    at async LongStandingScope._race (/tmp/playwright-java-947970650740572645/package/lib/utils/manualPromise.js:96:14)
    at async FrameDispatcher._handleCommand (/tmp/playwright-java-947970650740572645/package/lib/server/dispatchers/dispatcher.js:96:14)
    at async DispatcherConnection.dispatch (/tmp/playwright-java-947970650740572645/package/lib/server/dispatchers/dispatcher.js:361:22)
}

[mxschmitt]

Looks like upstream does waitForLoadState? https://github.com/microsoft/playwright/blob/77dee44984af1cd5b7c1ec4f6ed6fe022c7c55e6/tests/library/page-clock.spec.ts#L357

[yury-s]

Wait for url does wait for load state too by default and also ensures we are not on about:blank (unlikely).