Permanent ui-test-arm failure of fileDownloadTest

@JohanLorenzo

Log: https://treeherder.mozilla.org/logviewer?job_id=398214814&repo=reference-browser
This test fails permanently (times out: test runs too long and gets terminated).

First failure is for a9445a0, last successful run is befd344

Was bug 1800611 (cc @JohanLorenzo ) the only change between those A-C versions? This should not cause test issues - is this the only test which tries to save a file in any way?

@AndiAJ Please take a look next week.

Thanks for the ping! I wouldn't be surprised if the new version scheme breaks some assumptions. I can't access the Firebase logs on reference-browser. Would it be possible to get access to them?

For mozilla-mobile#2130 - Fix fileDownloadTest

For #2130 - Disable fileDownloadTest

The test is getting stuck for 30 minutes in the notification shade. Tried using the Fenix approach to scrolling the shade in #2135 but still timed out. Not sure why Fenix is working, but disabling for investigation so commits don't timeout.

For #2130 - Disable fileDownloadTest