XHR's pend forever when browser navigates in >= Chrome 71

[brian-mann]

As of Chrome 71 - Chrome now fires readystatechange events asynchronously when the page is unloading - which means these events are never received.

Because we're never notified when the XHR's are aborted internally by the browser we never finish them correctly - and awaiting them with cy.wait('...') never completes.

Electron:

Chrome >= 71:

[brian-mann]

Changed the implementation to no longer rely on internal XHR events to create a consistent experience between newer and older browsers.

There's now a new canceled XHR status to indicate the difference between calling xhr.abort() and the browser canceling the request due to page navigation.

[cypress-bot]

The code for this is done in cypress-io/cypress#3974, but has yet to be released.
We'll update this issue and reference the changelog when it's released.

[cypress-bot]

Released in 3.3.0.