[wdspec] fix browsingContext.navigationFailed test

[sadym-chromium]

Align webdriver/tests/bidi/browsing_context/navigation_failed/navigation_failed.py:test_with_new_navigation_inside_page and test_with_new_navigation with the spec. Currently, the test are not fully aligned with the spec, as the specific event depends on the document creation step, which in order depends on the fetch status.

When WPT trickles response, it sends headers and adds timeouts before sending the body. However, this does not guarantee the new document will not be created and activated:

• Navigate, step 22.9.
• Attempt to populate the history entry's document
  • step 5.2
    • Create navigation params by fetching, step 19.5.
    • Fetch request, step 15.
    • Run main fetch given fetchParams.
  • step 6.6.
    • load a document, step 2, case "HTML MIME type".
    • load an HTML document, step 1.
    • create and initialize a Document object, step 9.
    • Set during-loading navigation ID for WebDriver BiDi.

E.g. in case of Chromium, the document is created after the headers are received. This makes the discrepancy in the events have to be emitted. If the new document is created, it should be the "browsingContext.navigationAborted" event. If not, it should be "browsingContext.navigationFailed".

[sadym-chromium]

If in WPT we could pause sending back headers as well, we could create tests distinguishing between aborted and failed events.