Looks like testHistoryBackAndForwardAroundNTP is flakey in the ios_chrome_web_egtests target.

A recent example is https://ci.chromium.org/buildbot/internal.bling.main/ipad11-device-x64/6646

But going back to old builds, this seems to at least have been happening in the middle of July, likely goes farther back than that. I think it's time to disable this test.

+danyao@ +rohitrao@ +eugenebut@ who have been modifying navigation_egtest.mm.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ff3ecfded0fa31745422d9f12452d7baef2c3a69

commit ff3ecfded0fa31745422d9f12452d7baef2c3a69
Author: Sky Malice <skym@google.com>
Date: Wed Aug 22 00:25:33 2018

[iOS] Disable flakey testHistoryBackAndForwardAroundNTP.

Bug: 876449
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: Ib42fb716d79f95370f060af0a43fca7cb3288900
Reviewed-on: https://chromium-review.googlesource.com/1184141
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Sky Malice <skym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584933}
[modify] https://crrev.com/ff3ecfded0fa31745422d9f12452d7baef2c3a69/ios/chrome/browser/web/navigation_egtest.mm